Intentionally introduced storage deviations in a dispersed storage network

ABSTRACT

A method begins by a processing module receiving a first request to store a program. The method continues with the processing module determining first error coding dispersal storage function parameters and encoding a data segment of the program. The method continues with the processing module determining whether a second request to store the program is received. The method continues with the processing module encoding a second data segment of the program in accordance with the first error coding dispersal storage function parameters when the second request is not received. The method continues with the processing module changing the first error coding dispersal storage function parameters based on the another request to produce second error coding dispersal storage function parameters when the second request is received. The method continues with the processing module encoding the second data segment in accordance with the second error coding dispersal storage function parameters.

CROSS REFERENCE TO RELATED PATENTS

The present U.S. Utility patent application claims priority pursuant to35 U.S.C. §119(e) to U.S. Provisional Application Ser. No. 61/256,193,entitled “MEDIA DISTRIBUTION UTILIZING DISTRIBUTED STORAGE,” (AttorneyDocket No. CS277), filed Oct. 29, 2009, pending, which is herebyincorporated herein by reference in its entirety and made part of thepresent U.S. Utility patent application for all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

NOT APPLICABLE

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

NOT APPLICABLE

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

This invention relates generally to computing systems and moreparticularly to data storage solutions within such computing systems.

2. Description of Related Art

Computers are known to communicate, process, and store data. Suchcomputers range from wireless smart phones to data centers that supportmillions of web searches, stock trades, or on-line purchases every day.In general, a computing system generates data and/or manipulates datafrom one form into another. For instance, an image sensor of thecomputing system generates raw picture data and, using an imagecompression program (e.g., JPEG, MPEG, etc.), the computing systemmanipulates the raw picture data into a standardized compressed image.

With continued advances in processing speed and communication speed,computers are capable of processing real time multimedia data forapplications ranging from simple voice communications to streaming highdefinition video. As such, general-purpose information appliances arereplacing purpose-built communications devices (e.g., a telephone). Forexample, smart phones can support telephony communications but they arealso capable of text messaging and accessing the internet to performfunctions including email, web browsing, remote applications access, andmedia communications (e.g., telephony voice, image transfer, musicfiles, video files, real time video streaming. etc.).

Each type of computer is constructed and operates in accordance with oneor more communication, processing, and storage standards. As a result ofstandardization and with advances in technology, more and moreinformation content is being converted into digital formats. Forexample, more digital cameras are now being sold than film cameras, thusproducing more digital pictures. As another example, web-basedprogramming is becoming an alternative to over the air televisionbroadcasts and/or cable broadcasts. As further examples, papers, books,video entertainment, home video, etc. are now being stored digitally,which increases the demand on the storage function of computers.

A typical computer storage system includes one or more memory devicesaligned with the needs of the various operational aspects of thecomputer's processing and communication functions. Generally, theimmediacy of access dictates what type of memory device is used. Forexample, random access memory (RAM) memory can be accessed in any randomorder with a constant response time, thus it is typically used for cachememory and main memory. By contrast, memory device technologies thatrequire physical movement such as magnetic disks, tapes, and opticaldiscs, have a variable response time as the physical movement can takelonger than the data transfer, thus they are typically used forsecondary memory (e.g., hard drive, backup memory, etc.).

A computer's storage system will be compliant with one or more computerstorage standards that include, but are not limited to, network filesystem (NFS), flash file system (FFS), disk file system (DFS), smallcomputer system interface (SCSI), internet small computer systeminterface (iSCSI), file transfer protocol (FTP), and web-baseddistributed authoring and versioning (WebDAV). These standards specifythe data storage format (e.g., files, data objects, data blocks,directories, etc.) and interfacing between the computer's processingfunction and its storage system, which is a primary function of thecomputer's memory controller.

Despite the standardization of the computer and its storage system,memory devices fail; especially commercial grade memory devices thatutilize technologies incorporating physical movement (e.g., a discdrive). For example, it is fairly common for a disc drive to routinelysuffer from bit level corruption and to completely fail after threeyears of use. One solution is to a higher-grade disc drive, which addssignificant cost to a computer.

Another solution is to utilize multiple levels of redundant disc drivesto replicate the data into two or more copies. One such redundant driveapproach is called redundant array of independent discs (RAID). In aRAID device, a RAID controller adds parity data to the original databefore storing it across the array. The parity data is calculated fromthe original data such that the failure of a disc will not result in theloss of the original data. For example, RAID 5 uses three discs toprotect data from the failure of a single disc. The parity data, andassociated redundancy overhead data, reduces the storage capacity ofthree independent discs by one third (e.g., n−1=capacity). RAID 6 canrecover from a loss of two discs and requires a minimum of four discswith a storage capacity of n−2.

While RAID addresses the memory device failure issue, it is not withoutits own failures issues that affect its effectiveness, efficiency andsecurity. For instance, as more discs are added to the array, theprobability of a disc failure increases, which increases the demand formaintenance. For example, when a disc fails, it needs to be manuallyreplaced before another disc fails and the data stored in the RAIDdevice is lost. To reduce the risk of data loss, data on a RAID deviceis typically copied on to one or more other RAID devices. While thisaddresses the loss of data issue, it raises a security issue sincemultiple copies of data are available, which increases the chances ofunauthorized access. Further, as the amount of data being stored grows,the overhead of RAID devices becomes a non-trivial efficiency issue.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a schematic block diagram of an embodiment of a computingsystem in accordance with the invention;

FIG. 2 is a schematic block diagram of an embodiment of a computing corein accordance with the invention;

FIG. 3 is a schematic block diagram of an embodiment of a distributedstorage processing unit in accordance with the invention;

FIG. 4 is a schematic block diagram of an embodiment of a grid module inaccordance with the invention;

FIG. 5 is a diagram of an example embodiment of error coded data slicecreation in accordance with the invention;

FIG. 6 is a schematic block diagram of an embodiment of a mediadistribution system in accordance with the invention;

FIG. 7 is a flowchart illustrating an example of recording and playbackof media in accordance with the invention;

FIG. 8 is a schematic block diagram of another embodiment of a mediadistribution system in accordance with the invention;

FIG. 9 is another flowchart illustrating another example of recordingand playback of media in accordance with the invention;

FIG. 10 is a schematic block diagram of another embodiment of a mediadistribution system in accordance with the invention;

FIG. 11 is a schematic block diagram of another embodiment of a mediadistribution system in accordance with the invention;

FIG. 12 is another flowchart illustrating another example of recordingand playback of media in accordance with the invention;

FIG. 13 is a schematic block diagram of another embodiment of a mediadistribution system in accordance with the invention; and

FIG. 14 is a schematic block diagram of another embodiment of a mediadistribution system in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram of a computing system 10 thatincludes one or more of a first type of user devices 12, one or more ofa second type of user devices 14, at least one distributed storage (DS)processing unit 16, at least one DS managing unit 18, at least onestorage integrity processing unit 20, and a distributed storage network(DSN) memory 22 coupled via a network 24. The network 24 may include oneor more wireless and/or wire lined communication systems; one or moreprivate intranet systems and/or public internet systems; and/or one ormore local area networks (LAN) and/or wide area networks (WAN).

The DSN memory 22 includes a plurality of distributed storage (DS) units36 for storing data of the system. Each of the DS units 36 includes aprocessing module and memory and may be located at a geographicallydifferent site than the other DS units (e.g., one in Chicago, one inMilwaukee, etc.). The processing module may be a single processingdevice or a plurality of processing devices. Such a processing devicemay be a microprocessor, micro-controller, digital signal processor,microcomputer, central processing unit, field programmable gate array,programmable logic device, state machine, logic circuitry, analogcircuitry, digital circuitry, and/or any device that manipulates signals(analog and/or digital) based on hard coding of the circuitry and/oroperational instructions. The processing module may have an associatedmemory and/or memory element, which may be a single memory device, aplurality of memory devices, and/or embedded circuitry of the processingmodule. Such a memory device may be a read-only memory, random accessmemory, volatile memory, non-volatile memory, static memory, dynamicmemory, flash memory, cache memory, and/or any device that storesdigital information. Note that if the processing module includes morethan one processing device, the processing devices may be centrallylocated (e.g., directly coupled together via a wired and/or wireless busstructure) or may be distributedly located (e.g., cloud computing viaindirect coupling via a local area network and/or a wide area network).Further note that when the processing module implements one or more ofits functions via a state machine, analog circuitry, digital circuitry,and/or logic circuitry, the memory and/or memory element storing thecorresponding operational instructions may be embedded within, orexternal to, the circuitry comprising the state machine, analogcircuitry, digital circuitry, and/or logic circuitry. Still further notethat, the memory element stores, and the processing module executes,hard coded and/or operational instructions corresponding to at leastsome of the steps and/or functions illustrated in FIGS. 1-14.

Each of the user devices 12-14, the DS processing unit 16, the DSmanaging unit 18, and the storage integrity processing unit 20 may be aportable computing device (e.g., a social networking device, a gamingdevice, a cell phone, a smart phone, a personal digital assistant, adigital music player, a digital video player, a laptop computer, ahandheld computer, a video game controller, and/or any other portabledevice that includes a computing core) and/or a fixed computing device(e.g., a personal computer, a computer server, a cable set-top box, asatellite receiver, a television set, a printer, a fax machine, homeentertainment equipment, a video game console, and/or any type of homeor office computing equipment). Such a portable or fixed computingdevice includes a computing core 26 and one or more interfaces 30, 32,and/or 33. An embodiment of the computing core 26 will be described withreference to FIG. 2.

With respect to the interfaces, each of the interfaces 30, 32, and 33includes software and/or hardware to support one or more communicationlinks via the network 24 and/or directly. For example, interfaces 30support a communication link (wired, wireless, direct, via a LAN, viathe network 24, etc.) between the first type of user device 14 and theDS processing unit 16. As another example, DSN interface 32 supports aplurality of communication links via the network 24 between the DSNmemory 22 and the DS processing unit 16, the first type of user device12, and/or the storage integrity processing unit 20. As yet anotherexample, interface 33 supports a communication link between the DSmanaging unit 18 and any one of the other devices and/or units 12, 14,16, 20, and/or 22 via the network 24.

In general and with respect to data storage, the system 10 supportsthree primary functions: distributed network data storage management,distributed data storage and retrieval, and data storage integrityverification. In accordance with these three primary functions, data canbe distributedly stored in a plurality of physically different locationsand subsequently retrieved in a reliable and secure manner regardless offailures of individual storage devices, failures of network equipment,the duration of storage, the amount of data being stored, attempts athacking the data, etc.

The DS managing unit 18 performs distributed network data storagemanagement functions, which include establishing distributed datastorage parameters, performing network operations, performing networkadministration, and/or performing network maintenance. The DS managingunit 18 establishes the distributed data storage parameters (e.g.,allocation of virtual DSN memory space, distributed storage parameters,security parameters, billing information, user profile information,etc.) for one or more of the user devices 12-14 (e.g., established forindividual devices, established for a user group of devices, establishedfor public access by the user devices, etc.). For example, the DSmanaging unit 18 coordinates the creation of a vault (e.g., a virtualmemory block) within the DSN memory 22 for a user device (for a group ofdevices, or for public access). The DS managing unit 18 also determinesthe distributed data storage parameters for the vault. In particular,the DS managing unit 18 determines a number of slices (e.g., the numberthat a data segment of a data file and/or data block is partitioned intofor distributed storage) and a read threshold value (e.g., the minimumnumber of slices required to reconstruct the data segment).

As another example, the DS managing module 18 creates and stores,locally or within the DSN memory 22, user profile information. The userprofile information includes one or more of authentication information,permissions, and/or the security parameters. The security parameters mayinclude one or more of encryption/decryption scheme, one or moreencryption keys, key generation scheme, and data encoding/decodingscheme.

As yet another example, the DS managing unit 18 creates billinginformation for a particular user, user group, vault access, publicvault access, etc. For instance, the DS managing unit 18 tracks thenumber of times user accesses a private vault and/or public vaults,which can be used to generate a per-access bill. In another instance,the DS managing unit 18 tracks the amount of data stored and/orretrieved by a user device and/or a user group, which can be used togenerate a per-data-amount bill.

The DS managing unit 18 also performs network operations, networkadministration, and/or network maintenance. As at least part ofperforming the network operations and/or administration, the DS managingunit 18 monitors performance of the devices and/or units of the system10 for potential failures, determines the devices and/or unit'sactivation status, determines the devices' and/or units' loading, andany other system level operation that affects the performance level ofthe system 10. For example, the DS managing unit 18 receives andaggregates network management alarms, alerts, errors, statusinformation, performance information, and messages from the devices12-14 and/or the units 16, 20, 22. For example, the DS managing unit 18receives a simple network management protocol (SNMP) message regardingthe status of the DS processing unit 16.

The DS managing unit 18 performs the network maintenance by identifyingequipment within the system 10 that needs replacing, upgrading,repairing, and/or expanding. For example, the DS managing unit 18determines that the DSN memory 22 needs more DS units 36 or that one ormore of the DS units 36 needs updating.

The second primary function (i.e., distributed data storage andretrieval) begins and ends with a user device 12-14. For instance, if asecond type of user device 14 has a data file 38 and/or data block 40 tostore in the DSN memory 22, it send the data file 38 and/or data block40 to the DS processing unit 16 via its interface 30. As will bedescribed in greater detail with reference to FIG. 2, the interface 30functions to mimic a conventional operating system (OS) file systeminterface (e.g., network file system (NFS), flash file system (FFS),disk file system (DFS), file transfer protocol (FTP), web-baseddistributed authoring and versioning (WebDAV), etc.) and/or a blockmemory interface (e.g., small computer system interface (SCSI), internetsmall computer system interface (iSCSI), etc.). In addition, theinterface 30 may attach a user identification code (ID) to the data file38 and/or data block 40.

The DS processing unit 16 receives the data file 38 and/or data block 40via its interface 30 and performs a distributed storage (DS) process 34thereon (e.g., an error coding dispersal storage function). The DSprocessing 34 begins by partitioning the data file 38 and/or data block40 into one or more data segments, which is represented as Y datasegments. For example, the DS processing 34 may partition the data file38 and/or data block 40 into a fixed byte size segment (e.g., 2¹ to2^(n) bytes, where n=>2) or a variable byte size (e.g., change byte sizefrom segment to segment, or from groups of segments to groups ofsegments, etc.).

For each of the Y data segments, the DS processing 34 error encodes(e.g., forward error correction (FEC), information dispersal algorithm,or error correction coding) and slices (or slices then error encodes)the data segment into a plurality of error coded (EC) data slices 42-48,which is represented as X slices per data segment. The number of slices(X) per segment, which corresponds to a number of pillars n, is set inaccordance with the distributed data storage parameters and the errorcoding scheme. For example, if a Reed-Solomon (or other FEC scheme) isused in an n/k system, then a data segment is divided into n slices,where k number of slices is needed to reconstruct the original data(i.e., k is the threshold). As a few specific examples, the n/k factormay be 5/3; 6/4; 8/6; 8/5; 16/10.

For each slice 42-48, the DS processing unit 16 creates a unique slicename and appends it to the corresponding slice 42-48. The slice nameincludes universal DSN memory addressing routing information (e.g.,virtual memory addresses in the DSN memory 22) and user-specificinformation (e.g., user ID, file name, data block identifier, etc.).

The DS processing unit 16 transmits the plurality of EC slices 42-48 toa plurality of DS units 36 of the DSN memory 22 via the DSN interface 32and the network 24. The DSN interface 32 formats each of the slices fortransmission via the network 24. For example, the DSN interface 32 mayutilize an internet protocol (e.g., TCP/IP, etc.) to packetize theslices 42-48 for transmission via the network 24.

The number of DS units 36 receiving the slices 42-48 is dependent on thedistributed data storage parameters established by the DS managing unit18. For example, the DS managing unit 18 may indicate that each slice isto be stored in a different DS unit 36. As another example, the DSmanaging unit 18 may indicate that like slice numbers of different datasegments are to be stored in the same DS unit 36. For example, the firstslice of each of the data segments is to be stored in a first DS unit36, the second slice of each of the data segments is to be stored in asecond DS unit 36, etc. In this manner, the data is encoded anddistributedly stored at physically diverse locations to improved datastorage integrity and security. Further examples of encoding the datasegments will be provided with reference to one or more of FIGS. 2-14.

Each DS unit 36 that receives a slice 42-48 for storage translates thevirtual DSN memory address of the slice into a local physical addressfor storage. Accordingly, each DS unit 36 maintains a virtual tophysical memory mapping to assist in the storage and retrieval of data.

The first type of user device 12 performs a similar function to storedata in the DSN memory 22 with the exception that it includes the DSprocessing. As such, the device 12 encodes and slices the data fileand/or data block it has to store. The device then transmits the slices11 to the DSN memory via its DSN interface 32 and the network 24.

For a second type of user device 14 to retrieve a data file or datablock from memory, it issues a read command via its interface 30 to theDS processing unit 16. The DS processing unit 16 performs the DSprocessing 34 to identify the DS units 36 storing the slices of the datafile and/or data block based on the read command. The DS processing unit16 may also communicate with the DS managing unit 18 to verify that theuser device 14 is authorized to access the requested data.

Assuming that the user device is authorized to access the requesteddata, the DS processing unit 16 issues slice read commands to at least athreshold number of the DS units 36 storing the requested data (e.g., toat least 10 DS units for a 16/10 error coding scheme). Each of the DSunits 36 receiving the slice read command, verifies the command,accesses its virtual to physical memory mapping, retrieves the requestedslice, or slices, and transmits it to the DS processing unit 16.

Once the DS processing unit 16 has received a read threshold number ofslices for a data segment, it performs an error decoding function andde-slicing to reconstruct the data segment. When Y number of datasegments has been reconstructed, the DS processing unit 16 provides thedata file 38 and/or data block 40 to the user device 14. Note that thefirst type of user device 12 performs a similar process to retrieve adata file and/or data block.

The storage integrity processing unit 20 performs the third primaryfunction of data storage integrity verification. In general, the storageintegrity processing unit 20 periodically retrieves slices 45, and/orslice names, of a data file or data block of a user device to verifythat one or more slices have not been corrupted or lost (e.g., the DSunit failed). The retrieval process mimics the read process previouslydescribed.

If the storage integrity processing unit 20 determines that one or moreslices is corrupted or lost, it rebuilds the corrupted or lost slice(s)in accordance with the error coding scheme. The storage integrityprocessing unit 20 stores the rebuild slice, or slices, in theappropriate DS unit(s) 36 in a manner that mimics the write processpreviously described.

FIG. 2 is a schematic block diagram of an embodiment of a computing core26 that includes a processing module 50, a memory controller 52, mainmemory 54, a video graphics processing unit 55, an input/output (10)controller 56, a peripheral component interconnect (PCI) interface 58,at least one 10 device interface module 62, a read only memory (ROM)basic input output system (BIOS) 64, and one or more memory interfacemodules. The memory interface module(s) includes one or more of auniversal serial bus (USB) interface module 66, a host bus adapter (HBA)interface module 68, a network interface module 70, a flash interfacemodule 72, a hard drive interface module 74, and a DSN interface module76. Note the DSN interface module 76 and/or the network interface module70 may function as the interface 30 of the user device 14 of FIG. 1.Further note that the TO device interface module 62 and/or the memoryinterface modules may be collectively or individually referred to as TOports.

The processing module 50 may be a single processing device or aplurality of processing devices. Such a processing device may be amicroprocessor, micro-controller, digital signal processor,microcomputer, central processing unit, field programmable gate array,programmable logic device, state machine, logic circuitry, analogcircuitry, digital circuitry, and/or any device that manipulates signals(analog and/or digital) based on hard coding of the circuitry and/oroperational instructions. The processing module 50 may have anassociated memory and/or memory element, which may be a single memorydevice, a plurality of memory devices, and/or embedded circuitry of theprocessing module 50. Such a memory device may be a read-only memory,random access memory, volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, cache memory, and/or any devicethat stores digital information. Note that if the processing module 50includes more than one processing device, the processing devices may becentrally located (e.g., directly coupled together via a wired and/orwireless bus structure) or may be distributedly located (e.g., cloudcomputing via indirect coupling via a local area network and/or a widearea network). Further note that when the processing module 50implements one or more of its functions via a state machine, analogcircuitry, digital circuitry, and/or logic circuitry, the memory and/ormemory element storing the corresponding operational instructions may beembedded within, or external to, the circuitry comprising the statemachine, analog circuitry, digital circuitry, and/or logic circuitry.Still further note that, the memory element stores, and the processingmodule 50 executes, hard coded and/or operational instructionscorresponding to at least some of the steps and/or functions illustratedin FIGS. 1-14.

FIG. 3 is a schematic block diagram of an embodiment of a dispersedstorage (DS) processing module 34 of user device 12 and/or of the DSprocessing unit 16. The DS processing module 34 includes a gatewaymodule 78, an access module 80, a grid module 82, and a storage module84. The DS processing module 34 may also include an interface 30 and theDSnet interface 32 or the interfaces 68 and/or 70 may be part of user 12or of the DS processing unit 14. The DS processing module 34 may furtherinclude a bypass/feedback path between the storage module 84 to thegateway module 78. Note that the modules 78-84 of the DS processingmodule 34 may be in a single unit or distributed across multiple units.

In an example of storing data, the gateway module 78 receives anincoming data object that includes a user ID field 86, an object namefield 88, and the data field 40 and may also receive correspondinginformation that includes a process identifier (e.g., an internalprocess/application ID), metadata, a file system directory, a blocknumber, a transaction message, a user device identity (ID), a dataobject identifier, a source name, and/or user information. The gatewaymodule 78 authenticates the user associated with the data object byverifying the user ID 86 with the managing unit 18 and/or anotherauthenticating unit.

When the user is authenticated, the gateway module 78 obtains userinformation from the management unit 18, the user device, and/or theother authenticating unit. The user information includes a vaultidentifier, operational parameters, and user attributes (e.g., userdata, billing information, etc.). A vault identifier identifies a vault,which is a virtual memory space that maps to a set of DS storage units36. For example, vault 1 (i.e., user 1's DSN memory space) includeseight DS storage units (X=8 wide) and vault 2 (i.e., user 2's DSN memoryspace) includes sixteen DS storage units (X=16 wide). The operationalparameters may include an error coding algorithm, the width n (number ofpillars X or slices per segment for this vault), a read threshold T, awrite threshold, an encryption algorithm, a slicing parameter, acompression algorithm, an integrity check method, caching settings,parallelism settings, and/or other parameters that may be used to accessthe DSN memory layer.

The gateway module 78 uses the user information to assign a source name35 to the data. For instance, the gateway module 60 determines thesource name 35 of the data object 40 based on the vault identifier andthe data object. For example, the source name may contain a fileidentifier (ID), a vault generation number, a reserved field, and avault identifier (ID). As another example, the gateway module 78 maygenerate the file ID based on a hash function of the data object 40.Note that the gateway module 78 may also perform message conversion,protocol conversion, electrical conversion, optical conversion, accesscontrol, user identification, user information retrieval, trafficmonitoring, statistics generation, configuration, management, and/orsource name determination.

The access module 80 receives the data object 40 and creates a series ofdata segments 1 through Y 90-92 in accordance with a data storageprotocol (e.g., file storage system, a block storage system, and/or anaggregated block storage system). The number of segments Y may be chosenor randomly assigned based on a selected segment size and the size ofthe data object. For example, if the number of segments is chosen to bea fixed number, then the size of the segments varies as a function ofthe size of the data object. For instance, if the data object is animage file of 4,194,304 eight bit bytes (e.g., 33,554,432 bits) and thenumber of segments Y=131,072, then each segment is 256 bits or 32 bytes.As another example, if segment sized is fixed, then the number ofsegments Y varies based on the size of data object. For instance, if thedata object is an image file of 4,194,304 bytes and the fixed size ofeach segment is 4,096 bytes, the then number of segments Y=1,024. Notethat each segment is associated with the same source name.

The grid module 82 receives the data segments and may manipulate (e.g.,compression, encryption, cyclic redundancy check (CRC), etc.) each ofthe data segments before performing an error coding function of theerror coding dispersal storage function to produce a pre-manipulateddata segment. After manipulating a data segment, if applicable, the gridmodule 82 error encodes (e.g., Reed-Solomon, Convolution encoding,Trellis encoding, etc.) the data segment or manipulated data segmentinto X error coded data slices 42-44.

The value X, or the number of pillars (e.g., X=16), is chosen as aparameter of the error coding dispersal storage function. Otherparameters of the error coding dispersal function include a readthreshold T, a write threshold W, etc. The read threshold (e.g., T=10,when X=16) corresponds to the minimum number of error-free error codeddata slices required to reconstruct the data segment. In other words,the DS processing module 34 can compensate for X−T (e.g., 16−10=6)missing error coded data slices per data segment. The write threshold Wcorresponds to a minimum number of DS storage units that acknowledgeproper storage of their respective data slices before the DS processingmodule indicates proper storage of the encoded data segment. Note thatthe write threshold is greater than or equal to the read threshold for agiven number of pillars (X).

For each data slice of a data segment, the grid module 82 generates aunique slice name 37 and attaches it thereto. The slice name 37 includesa universal routing information field and a vault specific field and maybe 48 bytes (e.g., 24 bytes for each of the universal routinginformation field and the vault specific field). As illustrated, theuniversal routing information field includes a slice index, a vault ID,a vault generation, and a reserved field. The slice index is based onthe pillar number and the vault ID and, as such, is unique for eachpillar (e.g., slices of the same pillar for the same vault for anysegment will share the same slice index). The vault specific fieldincludes a data name, which includes a file ID and a segment number(e.g., a sequential numbering of data segments 1-Y of a simple dataobject or a data block number).

Prior to outputting the error coded data slices of a data segment, thegrid module may perform post-slice manipulation on the slices. Ifenabled, the manipulation includes slice level compression, encryption,CRC, addressing, tagging, and/or other manipulation to improve theeffectiveness of the computing system.

When the error coded data slices of a data segment are ready to beoutputted, the grid module 82 determines which of the DS storage units36 will store the EC data slices based on a dispersed storage memorymapping associated with the user's vault and/or DS storage unitattributes. The DS storage unit attributes may include availability,self-selection, performance history, link speed, link latency,ownership, available DSN memory, domain, cost, a prioritization scheme,a centralized selection message from another source, a lookup table,data ownership, and/or any other factor to optimize the operation of thecomputing system. Note that the number of DS storage units 36 is equalto or greater than the number of pillars (e.g., X) so that no more thanone error coded data slice of the same data segment is stored on thesame DS storage unit 36. Further note that EC data slices of the samepillar number but of different segments (e.g., EC data slice 1 of datasegment 1 and EC data slice 1 of data segment 2) may be stored on thesame or different DS storage units 36.

The storage module 84 performs an integrity check on the outboundencoded data slices and, when successful, identifies a plurality of DSstorage units based on information provided by the grid module 82. Thestorage module 84 then outputs the encoded data slices 1 through X ofeach segment 1 through Y to the DS storage units 36. Each of the DSstorage units 36 stores its EC data slice(s) and maintains a localvirtual DSN address to physical location table to convert the virtualDSN address of the EC data slice(s) into physical storage addresses.

In an example of a read operation, the user device 12 and/or 14 sends aread request to the DS processing unit 14, which authenticates therequest. When the request is authentic, the DS processing unit 14 sendsa read message to each of the DS storage units 36 storing slices of thedata object being read. The slices are received via the DSnet interface32 and processed by the storage module 84, which performs a parity checkand provides the slices to the grid module 82 when the parity check wassuccessful. The grid module 82 decodes the slices in accordance with theerror coding dispersal storage function to reconstruct the data segment.The access module 80 reconstructs the data object from the data segmentsand the gateway module 78 formats the data object for transmission tothe user device.

FIG. 4 is a schematic block diagram of an embodiment of a grid module 82that includes a control unit 73, a pre-slice manipulator 75, an encoder77, a slicer 79, a post-slice manipulator 81, a pre-slice de-manipulator83, a decoder 85, a de-slicer 87, and/or a post-slice de-manipulator 89.Note that the control unit 73 may be partially or completely external tothe grid module 82. For example, the control unit 73 may be part of thecomputing core at a remote location, part of a user device, part of theDS managing unit 18, or distributed amongst one or more DS storageunits.

In an example of write operation, the pre-slice manipulator 75 receivesa data segment 90-92 and a write instruction from an authorized userdevice. The pre-slice manipulator 75 determines if pre-manipulation ofthe data segment 90-92 is required and, if so, what type. The pre-slicemanipulator 75 may make the determination independently or based oninstructions from the control unit 73, where the determination is basedon a computing system-wide predetermination, a table lookup, vaultparameters associated with the user identification, the type of data,security requirements, available DSN memory, performance requirements,and/or other metadata.

Once a positive determination is made, the pre-slice manipulator 75manipulates the data segment 90-92 in accordance with the type ofmanipulation. For example, the type of manipulation may be compression(e.g., Lempel-Ziv-Welch, Huffman, Golomb, fractal, wavelet, etc.),signatures (e.g., Digital Signature Algorithm (DSA), Elliptic Curve DSA,Secure Hash Algorithm, etc.), watermarking, tagging, encryption (e.g.,Data Encryption Standard, Advanced Encryption Standard, etc.), addingmetadata (e.g., time/date stamping, user information, file type, etc.),cyclic redundancy check (e.g., CRC32), and/or other data manipulationsto produce the pre-manipulated data segment.

The encoder 77 encodes the pre-manipulated data segment 92 using aforward error correction (FEC) encoder (and/or other type of erasurecoding and/or error coding) to produce an encoded data segment 94. Theencoder 77 determines which forward error correction algorithm to usebased on a predetermination associated with the user's vault, a timebased algorithm, user direction, DS managing unit direction, controlunit direction, as a function of the data type, as a function of thedata segment 92 metadata, and/or any other factor to determine algorithmtype. The forward error correction algorithm may be Golay,Multidimensional parity, Reed-Solomon, Hamming, Bose Ray ChauduriHocquenghem (BCH), Cauchy-Reed-Solomon, or any other FEC encoder. Notethat the encoder 77 may use a different encoding algorithm for each datasegment 92, the same encoding algorithm for the data segments 92 of adata object, or a combination thereof.

The encoded data segment 94 is of greater size than the data segment 92by the overhead rate of the encoding algorithm by a factor of X/T, whereX is the width or number of slices, and T is the read threshold. In thisregard, the corresponding decoding process can accommodate at most X-Tmissing EC data slices and still recreate the data segment 92. Forexample, if X=16 and T=10, then the data segment 92 will be recoverableas long as 10 or more EC data slices per segment are not corrupted.

The slicer 79 transforms the encoded data segment 94 into EC data slicesin accordance with the slicing parameter from the vault for this userand/or data segment 92. For example, if the slicing parameter is X=16,then the slicer 79 slices each encoded data segment 94 into 16 encodedslices.

The post-slice manipulator 81 performs, if enabled, post-manipulation onthe encoded slices to produce the EC data slices. If enabled, thepost-slice manipulator 81 determines the type of post-manipulation,which may be based on a computing system-wide predetermination,parameters in the vault for this user, a table lookup, the useridentification, the type of data, security requirements, available DSNmemory, performance requirements, control unit directed, and/or othermetadata. Note that the type of post-slice manipulation may includeslice level compression, signatures, encryption, CRC, addressing,watermarking, tagging, adding metadata, and/or other manipulation toimprove the effectiveness of the computing system.

In an example of a read operation, the post-slice de-manipulator 89receives at least a read threshold number of EC data slices and performsthe inverse function of the post-slice manipulator 81 to produce aplurality of encoded slices. The de-slicer 87 de-slices the encodedslices to produce an encoded data segment 94. The decoder 85 performsthe inverse function of the encoder 77 to recapture the data segment90-92. The pre-slice de-manipulator 83 performs the inverse function ofthe pre-slice manipulator 75 to recapture the data segment 90-92.

FIG. 5 is a diagram of an example of slicing an encoded data segment 94by the slicer 79. In this example, the encoded data segment 94 includesthirty-two bits, but may include more or less bits. The slicer 79disperses the bits of the encoded data segment 94 across the EC dataslices in a pattern as shown. As such, each EC data slice does notinclude consecutive bits of the data segment 94 reducing the impact ofconsecutive bit failures on data recovery. For example, if EC data slice2 (which includes bits 1, 5, 9, 13, 17, 25, and 29) is unavailable(e.g., lost, inaccessible, or corrupted), the data segment can bereconstructed from the other EC data slices (e.g., 1, 3 and 4 for a readthreshold of 3 and a width of 4).

FIG. 6 is a schematic block diagram of an embodiment of a mediadistribution system. As illustrated, the system includes a plurality ofviewers 1-V, a plurality of set top boxes 1-V, the DS processing unit16, the DSN memory 22, and a distribution unit 96.

The distribution unit 96 may be a portable computing device (e.g., asocial networking device, a gaming device, a cell phone, a smart phone,a personal digital assistant, a digital music player, a digital videoplayer, a laptop computer, a handheld computer, a video game controller,and/or any other portable device that includes a computing core) and/ora fixed computing device (e.g., a personal computer, a computer server,a cable set-top box, a satellite receiver, a television set, a printer,a fax machine, home entertainment equipment, a video game console,and/or any type of home or office computing equipment). The distributionunit 96 includes a computing core 26, one or more interfaces 30, 32,and/or 33, and may include a DS processing 34. As illustrated, a viewerincludes a flat panel television having a display and speakers toreproduce the media 100 that is coupled to a set top box.

The set top box (e.g., cable, satellite, land-line, twisted pair, fiberoptics, Internet, etc.) includes the computing core 26 and may includethe DS processing 34 to receive media slices from the playback DSNmemory 194, de-slice, and decode to produce the media 100 for viewing.In addition, the top box 1-V may directly select content 98 (e.g.,broadcast/multicast or on-demand video over cable, satellite and/or theinternet) and/or may select stored content 98 from the DSN memory 22 viathe distribution unit 96. The functions of the set top box and viewermay be integrated together. For example, the viewer (e.g., including settop box functionality) may connect either directly to the DSN memory 22to retrieve media slices 100 or through the distribution unit 96 toreceive media 100. The DS processing unit 16 receives content 98 andstore error coded data slices in the DSN memory 22 as described in moredetail below.

The set top box sends control commands to the distribution unit 96and/or DS processing unit 16. The commands may include one or more ofrecord, playback, pause, skip forward, skip backwards, and delete. Forexample, the set top box sends a record command to the DS processingunit 16. In response, DS processing unit 16 captures a program (e.g.,all or a portion of the content 98) and stores the program as errorcoded data slices in the DSN memory 22 and information that uniquelyidentifies the particular set top box. In another example, the set topbox sends a playback command to the distribution unit 96. In response,the distribution unit 96 retrieves error coded data slices from the DSNmemory 22 in accordance with the information that uniquely identifiesthe particular set top box and sends the slices to the set top box.

The DS unit 16 determines which portion of the content 98 to store inthe DSN memory 22. Such a determination may be based on one or more of acommand, a command from the set top box, a command from the distributionunit 96, and/or a predetermination. For example, set top box 2 may senda record command to the distribution unit 96 where the record commandincludes a command to record the 5:30 pm evening news program via cablechannel 188 on October 18. The distribution unit 96 processes the recordcommand by sending a store command to the DS processing unit 16. The DSunit 16 queues the store command and executes the store command onOctober 18 at 5:30 pm. The DS unit 16 executes the store command byselecting the content 98 from cable channel 188 and receiving thecontent 98. Next, the DS unit 16 determines record operationalparameters (e.g., pillar width n, write threshold, encoding method,slicing method, encryption method, etc.) and may further determineunique information associated with the requesting set top box (e.g.,identification information, unique retrieval sequence information,addressing information, etc.). The DS processing unit 16 determines therecord operational parameters based on one or more of a command, acommand from the distribution unit 96, an estimated number of storecommands received for the same content indicator, a system performanceindicator, a memory utilization indicator, a policy indicator, a totalpopulation of set top boxes indicator, and a predetermination. Next, theDS unit 16 determines which DS units 36 to store the EC data slices andsends the EC data slices 100 with a store command to the selected DSunits 36 of the DSN memory 22 for storage therein.

The DS processing unit 16 encodes the program in accordance with therecord operational parameters to produce error coded data slices. The DSprocessing unit 16 initiates storage the error coded data slices in theDS unit 36 and the unique information associated with the requesting settop box.

For subsequent requests to record the same program from other set topboxes, the DS processing unit 16 executes a record function. Forexample, the DS processing unit 16 may only store EC data slicesproduced from content 98 in response to receiving at least one recordcommand from at least one set top box. In another example, thedistribution unit 96 sends a record command to the DS processing unit 16based on receiving a first record command for the content 98 and sendsnothing to the DS processing unit 16 when the distribution unit 96receives a second record command for the same content 98. In otherwords, the first record command for a given content portion invokesstoring the content 98 as slices 100 to the DSN memory 22 and any othersubsequent record commands for the same content 98 do not change thestoring of that content 98 as slices 100 in the DSN memory 22.

In yet another example, the distribution unit 96 sends the store commandto the DS processing unit 16 based on receiving a first or more recordcommands for the content portion where subsequent record requests mayalter the record operational parameters. In other words, the firstrecord command for a given content portion invokes storing the content98 as EC data slices to the DSN memory 22 and any other subsequentrecord commands for the same content 98 may change the recordoperational parameters of that content 98. In an instance, the DSprocessing unit 16 may start with a 32/26 system and store slices topillars 1-27 for the first viewer. The DS processing unit 16 maycontinue to store slices but to pillars 2-28 when the second viewerrequests to record the same content portion. The DS processing unit 16may change a slicing pillar width/read threshold from a 32/26 system toa 40/26 system yet storing to at least 32 pillars of the 40 to realizestoring 32 of 40 pillars in some 76 million combinations and still haveover 900 thousand combinations to read 26 pillars from the 32 storedpillars when even more viewers request to record the same contentportion. The distribution unit 96 and/or DS processing unit 16 maychange the record operational parameters prior to or during contentcapture.

As another example, the distribution unit 96 and/or DS processing unit16 determines read operational parameters (e.g., pillar width n, whichparticular pillars are allowed to read, read threshold, decoding method,de-slicing method, decryption method, etc.) in response to receiving arecord and/or playback request. Such a determination may be based on oneor more of a request, a command, the number of store requests receivedfor the same content 98, an estimated number of store requests receivedfor the same content indicator, which combinations of pillars havealready been assigned (e.g., the read operational parameters of otherviewers), a system performance indicator, a memory utilizationindicator, a pillar availability indicator, a policy indicator, a totalpopulation of set top boxes indicator, and/or a predetermination. Forexample, the DS processing unit 16 assigns set top box 1 readoperational parameters to read from pillars 1-10 while assigning set topbox 2 read operational parameters to read from pillars 3-12 when thesystem has 16 pillars and a read threshold of 10 and both set top boxeshave requested the same content program. In addition, the DS processingunit 16 may assign each set top box more than one combination of allowedread pillars to improve the read reliability. The read operationalparameters may be utilized in the DS processing 34 (e.g., in thedistribution unit 96 and/or the set top box/viewer) to subsequentlydecode retrieved EC data slices 100 from the allowed read pillars toproduce a desired program of the content 98. The method of operation ofthe DS processing unit and distribution unit 96 is discussed in greaterdetail with reference to FIG. 7.

Note that the number of read pillar combinations can be expressed as:

Read combinations=n!/k!(n−k)! where n=pillar width, k=read threshold

Further note that the minimum number of unique read combinations isgreater than or equal to the estimated number of viewers that record thesame content portion. For example, at most 8,008 unique viewers (eachwith one read pillar combination) can be supported when the pillar widthis 16 and the read threshold is 10. In another example, at most 90,619unique viewers (each with ten read pillar combinations to choose from)can be supported when the pillar width is 32 and the read threshold is26. In other words, there are 906,192 unique ways to choose 26 pillarsfrom 32 and the viewer may be assigned 10 of those ways to only read 26of the 32 pillars. Adding more combinations per user may improve thereliability of decoding slices 100 into data segments but may also lowerthe number of viewers than are allowed to record the same contentportion.

In a playback scenario, the set top box sends a playback request to thedistribution unit 96 to invoke the retrieval of stored EC data slicesfrom the DSN memory 22. The distribution unit 96 determines if uniqueread operational parameters have been assigned for this set top boxbased on a list lookup (e.g., a media object table and/or user vault).Note that the unique read operational parameters may established whenthe set top box initiated the record command or when the set to boxinitiated the playback command. Further note that the read operationalparameters determination may be based on one or more of the recordoperational parameters, a command, the number of store commands receivedfor the same program of the content 98, an estimated number of storecommands received for the same content indicator, which combinations ofpillars have already been assigned (e.g., the read operationalparameters of other viewers), a system performance indicator, a memoryutilization indicator, a pillar availability indicator, a policyindicator, a total population of set top boxes indicator, and/or apredetermination.

Next, the distribution unit 96 determines the DS units 36 based on themedia object ID and/or the read operational parameters. The distributionunit 96 may utilize a first combination of read operational parametersto attempt to retrieve and decode the EC data slices from the DS units36. The distribution unit 96 determines if the slice retrieval anddecoding is successful. The distribution unit 96 may utilize a secondcombination of read operational parameters to attempt to retrieve anddecode the slices 100 when the distribution unit 96 determines that theattempt utilizing the first combination of read operational parameterswas not successful. The distribution unit 96 continues this processuntil all the assigned combinations of read operational parameters havebeen tried. Note that the distribution unit 96 may utilize readoperational parameters that vary from data segment to data segment. Forexample, the distribution unit 96 may utilize retrieved EC data slicesfrom pillars 1, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 to produce a first datasegment and may utilize retrieved EC data slices from pillars 1, 4, 5,6, 7, 8, 9, 10, 11, 12, 13 to produce a second data segment.

The distribution unit 96 may assign at least one additional combinationof read operational parameters when the distribution unit 96 determinesthat all of the previously assigned combinations of read operationalparameters have been tried without success (e.g., failure of decodingthe data segment from available slices 100). Note that the at least oneadditional combination of read operational parameters is unique withrespect to all of the other combinations of read operational parametersassigned to other viewers/set top boxes for one or more data segments.For example, the set top box may be assigned four combinations of readpillars to utilize to retrieve and decode EC data slices. Thedistribution unit 96 attempts to utilize the first combination and willdetermine if that is successful. The distribution unit 96 continues totry each of the four combinations until it finds a combination that issuccessful. The distribution unit 96 determines an additionalcombination if the previously assigned combination(s) all fail. Thedistribution unit 96 retrieves, de-slices, and decodes the EC dataslices to produce the program when a successful combination of readoperational parameters is utilized. The distribution unit 96 sends theEC data slices and/or the decoded program to a set top box requestingplayback. The method of operation of the set top box, DS processing unit16, and distribution unit 96 is discussed in greater detail withreference to FIG. 7.

FIG. 7 is a flowchart illustrating an example of recording and playbackof media. The method begins at step 102 where a processing module (e.g.,of the distribution unit 96) receives a viewer command (e.g., a set topbox request), a viewer ID, and media object identifier (ID). The mediaobject ID is an identifier for the program portion of the content 98.For example, media object ID 3017301881018 may correspond to the 30minute 5:30 pm evening news on cable channel 188 on October 18. At step104 the processing module determines if the command is a record requestor a playback request by examining the received command.

At step 106 the processing module determines if this is the firstrequest to record the media object when the processing module determinesthat the command is the record command. Such a determination may bebased on one or more of reading a vault media object table, reading alocal media object table, and requesting information in a media objecttable from the DS processing unit/distribution unit. The media objecttable may list the identity of the set top boxes that have requested torecord the same media object ID. The processing module determines thatthis is the first request to record the media object when the mediaobject table indicates no other viewers have requested to record thesame media object ID. Note that the processing module may receive aplurality of requests to record a broadcast of data. The method branchesto step 114 to determine the read operational parameters when theprocessing module determines that this is not the first request torecord the media object.

At step 110 the processing module determines the record operationalparameters when the processing module determines that this is the firstrequest to record the media object (e.g., pillar width n, writethreshold, encoding method, slicing method, encryption method,encryption key, etc.). Such a determination of the record operationalparameters may be based on one or more of a command, a command from thedistribution unit/DS processing unit, an estimated number of storecommands received for the same content indicator, a system performanceindicator, a memory utilization indicator, a policy indicator, a totalpopulation of set top boxes indicator, and a predetermination. Theprocessing module updates the media object table to include a requestingdevice ID and record operational parameters associated with the mediaobject ID.

At step 112 the processing module sends the DS processing unit a storecommand message where the message includes the store command, the mediaobject ID, and the record operational parameters. Additionally, theprocessing module encodes the data using an error coding dispersalstorage function an in accordance with the record operational parametersto produce a plurality of sets of encoded data slices (e.g., EC dataslice sets for each data segment) when the data is broadcast and inresponse to a request of the plurality of requests.

At step 114 the processing module generates read operational parametersfor this media object in the form of a unique retrieval matrix for eachof the plurality of requests based on an identity of a requesting deviceand the error coding dispersal storage function to produce a pluralityof unique retrieval matrixes. Alternatively, the processing moduledetermines the read operational parameters in response to receiving aplayback command as discussed below with reference to step 118. Theprocessing module generates the unique retrieval matrix based on atleast one of a data identifier, a unique retrieval matrix associatedwith at least one other requesting device (e.g., those alreadyassigned), a unique retrieval matrix not associated with any otherrequesting device (e.g., those not already assigned), and a uniqueretrieval matrix functionality indicator (e.g., an operational statusindicator). Note that the plurality of unique retrieval matrixesincludes a plurality of collectives of pillar identifiers, wherein eachcollective includes pillar identifiers corresponding to at least one ofthe plurality of sets of encoded data slices for retrievingcorresponding encoded data slices. The collective identifies a set ofpillar identifiers for one or more data segments. Further note that anindividual unique retrieval matrix includes one or more of a pillarslist, a segmenting protocol, a pre-slice data manipulation function, aforward error correction encoding function, a slicing pillar width, apost-slice data manipulation function, a write threshold, and a readthreshold. Note that the pillars list includes one of at least onecollective of pillar identifiers associated with less than a slicingpillar width number and at least the read threshold number of aplurality of dispersed storage (DS) units associated with the DSNmemory, and at least one collective of pillar identifiers associatedwith less than the slicing pillar width number and at least the readthreshold number of the plurality of DS units, wherein the at least onecollective of pillar identifiers is unique as compared to every othercollective of pillar identifiers associated with previously determinedunique retrieval matrixes for the same set of the plurality of sets ofencoded data slices. In other words, no other requesting device isassigned the same plurality of collectives of pillar identifiers forthis data. At step 116, the processing module stores the plurality ofsets of encoded data slices and the plurality of unique retrievalmatrixes in a dispersed storage network (DSN) memory as a plurality ofunique copies of the data.

The processing module receives a plurality of playback requests for datafrom a plurality of requesting devices, wherein the data is encoded viaan error coding dispersal storage function to produce a plurality ofsets of encoded data slices which are stored in a dispersed storagenetwork (DSN) memory. At step 118 the processing module determines theread operational parameters for each of the plurality of playbackrequests. The processing module determines the read operationalparameters by statically or dynamically obtaining a plurality of uniqueretrieval matrixes based on identities of the plurality of requestingdevices. In an example of the static method, the processing moduleretrieves the plurality of unique retrieval matrixes from the DSN memorybased on the identities of the plurality of requesting devices (e.g., alookup of the assignment from a previous playback request or a recordrequest).

In an example of the dynamic method, the processing module generates aunique retrieval matrix for each of the plurality of playback requestsbased on one or more of the identities of the plurality of requestingdevices, the error coding dispersal storage function, a data identifier,a unique retrieval matrix associated with at least one other requestingdevice, and a unique retrieval matrix functionality indicator. Note thatthe unique retrieval matrix includes one or more of a pillars list, asegmenting protocol, a pre-slice data manipulation function, a forwarderror correction encoding function, a slicing pillar width, a post-slicedata manipulation function, a write threshold, and a read threshold.Further note that the pillars list includes one of at least onecollective of pillar identifiers associated with less than a slicingpillar width number and at least the read threshold number of aplurality of dispersed storage (DS) units associated with the DSN memoryor at least one collective of pillar identifiers associated with lessthan the slicing pillar width number and at least the read thresholdnumber of the plurality of DS units, wherein the at least one collectiveof pillar identifiers is unique as compared to every other collective ofpillar identifiers associated with previously determined uniqueretrieval matrixes for the same set of the plurality of sets of encodeddata slices.

At step 120 the processing module determines the present (e.g., asequential data segment) plurality of error coded slice namescorresponding to the slices of the data by transforming the data ID(e.g., object name) into the slice names. In addition at step 120 theprocessing module determines DS units based on one or more of the uniqueretrieval matrix pillars list, the data ID, a translation of the data IDto a virtual DSN address, and a lookup of the virtual DSN address tophysical location table. For example, the processing module determinesto retrieve from DS units 3, 4, 5, 6, 7, 11, 12, 13, 15, 16 when theunique retrieval matrix pillars list for a present collective of errorcoded data slices includes the pillars corresponding to DS units 3, 4,5, 6, 7, 11, 12, 13, 15, 16 even when the virtual DSN address tophysical location table includes DS units 1-16 for the data.

At step 122 the processing module sends the DS units retrieve slicecommands and at step 124 receives the EC data slices to retrieve, fromthe DSN memory, a plurality of unique copies of the plurality of sets ofencoded data slices in accordance with the plurality of unique retrievalmatrixes. For example, the processing module retrieves one set of errorcoded data slices, corresponding to a data segment, at a time retrievingthe slices from DS units associated with the pillars of the pillars listfrom the unique retrieval matrix associated with the data segment.Additionally, the processing module may output a unique copy of theplurality of unique copies of the plurality of sets of encoded dataslices to a corresponding requesting device. Additionally, at step 126,the processing module may decode a unique copy of the plurality ofunique copies of the plurality of sets of encoded data slices inaccordance with the error coding dispersal storage function to produce aunique copy of the data. Next, the processing module outputs the uniquecopy of the data to a corresponding requesting device.

Note that the set top box/viewer includes DS processing to convert theEC data slices into the media object for the viewer. Alternatively, theset top box/viewer may process media object data received from theprocessing module of the distribution unit including video or audio orvideo and audio in a real time stream. The set top box/viewer may sendflow control commands (e.g., pause, stop, rewind, fast forward, skipbackwards, skip forwards, etc.) to the distribution unit such that thedistribution unit varies the real time stream in response to thecommands.

In another example of a record and playback scenario, a method beginswhere a processing module receives a plurality of record requests torecord a broadcast of data. The processing module encodes the data usingan error coding dispersal storage function to produce a plurality ofsets of encoded data slices when the data is broadcast and in responseto a record request of the plurality of record requests. The processingmodule generates a list of requesting device identities corresponding tothe plurality of requests. Next, the processing module stores theplurality of sets of encoded data slices and the list of requestingdevice identities in a dispersed storage network (DSN) memory. As aspecific example, the processing module encodes the list using the errorcoding dispersal storage function to produce list data slices and storesthe slices in the DSN memory. Alternatively, or in addition to storingthe slices in the DSN memory, the processing module stores the list dataslices in a local memory

The example continues where the processing module receives a playbackrequest from a device identified in the list of requesting deviceidentities (e.g., the processing module receives a request and verifiesthat the device ID is in the list). The processing module generates aunique retrieval matrix for the device based in part on the error codingdispersed storage function. Note that the unique retrieval matrixincludes a collective of pillar identifiers, wherein the collectiveincludes pillar identifiers corresponding to at least one of theplurality of sets of encoded data slices for retrieving correspondingencoded data slices. Note that the collective may identify pillarscorresponding to one or more data segments). Further note that theunique retrieval matrix includes one or more of a pillars list, asegmenting protocol, a pre-slice data manipulation function, a forwarderror correction encoding function, a slicing pillar width, a post-slicedata manipulation function, a write threshold, and a read threshold.Note that the pillars list includes at least one collective of pillaridentifiers associated with less than a slicing pillar width number andat least the read threshold number of a plurality of dispersed storage(DS) units associated with the DSN memory or at least one collective ofpillar identifiers associated with less than the slicing pillar widthnumber and at least the read threshold number of the plurality of DSunits, wherein the at least one collective of pillar identifiers isunique as compared to every other collective of pillar identifiersassociated with previously determined unique retrieval matrixes for thesame set of the plurality of sets of encoded data slices. For instance,no other requesting device is assigned the same combination of pillarsfor each data segment. Additionally, the processing module may generatethe unique retrieval matrix based on at least one of a data identifier,a unique retrieval matrix associated with at least one other requestingdevice identified in the list of requesting device identities (e.g.,already assigned), a unique retrieval matrix not associated with anyother requesting device identified in the list of requesting deviceidentities (e.g., potentially available for assignment), and a uniqueretrieval matrix functionality indicator (e.g., an operational readinessindicator of associated DS unit status).

The example continues where the processing module outputs a uniqueplurality of sets of encoded data slices from the plurality of sets ofencoded data slices in accordance with the unique retrieval matrix. Forinstance, the processing module retrieves the unique plurality of setsof encoded data slices from the DSN memory in accordance with the uniqueretrieval matrix (e.g., from the unique plurality of pillar collectives)and sends the slices to the requesting device. Additionally, theprocessing module may decode the unique plurality of sets of encodeddata slices in accordance with the error coding dispersal storagefunction to produce a unique copy of the data, and output the uniquecopy of the data to the device. Additionally, the processing module mayreceive a second playback request from the device and generate a secondunique retrieval matrix for the device based on the error codingdispersed storage function.

Next, the processing module outputs a second unique plurality of sets ofencoded data slices from the plurality of sets of encoded data slices inaccordance with the second unique retrieval matrix. For instance, therequesting device is assigned a different unique retrieval matrix foreach playback of the data. Additionally, the processing module may storethe unique retrieval matrix for the device in the DSN memory and receivea subsequent playback request from the device.

Next, the processing module retrieves the unique retrieval matrix forthe device from the DSN memory and outputs the unique plurality of setsof encoded data slices from the plurality of sets of encoded data slicesin accordance with the unique retrieval matrix. For instance, theprocessing module utilizes the same unique retrieval matrix for thedevice for each playback of the data. Additionally, the processingmodule may output the unique retrieval matrix for the device to thedevice and receive a subsequent playback request from the device,wherein the request includes the unique retrieval matrix for the device.Next, the processing module outputs the unique plurality of sets ofencoded data slices from the plurality of sets of encoded data slices inaccordance with the unique retrieval matrix.

FIG. 8 is a schematic block diagram of another embodiment of a mediadistribution system. As illustrated, the system includes a plurality ofviewers 1-V, a plurality of set top boxes 1-V, the DS processing unit16, the DSN memory 22, and a distribution unit 96. The plurality ofviewers 1-V, the plurality of set top boxes 1-V, the DS processing unit16, the DSN memory 22, and the distribution unit 96 operate inaccordance with, but not limited to, the operations as describedpreviously with reference to FIG. 6.

In an example of operation, a processing module (e.g., of thedistribution unit) receives a plurality of requests to retrieve a storedprogram that is stored as a plurality of sets of encoded data slices inaccordance with record error coding dispersal storage functionparameters in a dispersed storage network (DSN) memory. The processingmodule receives a first one of the plurality of requests and determinesfirst playback error coding dispersal storage function parameters basedon the request and the record error coding dispersal storage functionparameters. The processing module retrieves a first set of the pluralityof sets of encoded data slices based on the first playback error codingdispersal storage function parameters.

Next, the processing module outputs the first set of the plurality ofsets of encoded data slices to a first requesting device associated withthe first one of the plurality of requests. The processing moduledecodes the first set of the plurality of sets of encoded data slicesbased on the first playback error coding dispersal storage functionparameters to produce first recovered data. In addition, the processingmodule may send the first recovered data to the first requesting device.Next, the processing module modifies the record error coding dispersalstorage function parameters based on the first request and the recorderror coding dispersal storage function parameters to produce modifiedrecord error coding dispersal storage function parameters. For instance,the processing module changes the record error coding dispersal storagefunction parameters after each retrieval. Next, the processing moduleencodes the first recovered data in accordance with the modified recorderror coding dispersal storage function parameters to produce a firstmodified set of the plurality of sets of encoded data slices. Theprocessing module stores the first modified set of the plurality of setsof encoded data slices in the DSN memory. The processing module receivesa second one of the plurality of requests and determines second playbackerror coding dispersal storage function parameters based on the requestand the modified record error coding dispersal storage functionparameters. The processing module retrieves the first modified set ofthe plurality of sets of encoded data slices based on the secondplayback error coding dispersal storage function parameters from the DSNmemory.

Next, the processing module outputs the first set of the plurality ofsets of encoded data slices to a second requesting device associatedwith the second one of the plurality of requests. The processing moduledecodes the first set of the plurality of sets of encoded data slicesbased on the second playback error coding dispersal storage functionparameters to produce the first recovered data. In addition, theprocessing module may send the first recovered data to the secondrequesting device.

Next, the processing module modifies the modified record error codingdispersal storage function parameters based on the second request andthe modified record error coding dispersal storage function parametersto produce further modified record error coding dispersal storagefunction parameters. Note that the processing module changes the recordparameters after each retrieval.

Next, the processing module encodes the first recovered data inaccordance with the further modified record error coding dispersalstorage function parameters to produce a first further modified set ofthe plurality of sets of encoded data slices. Note that the slices aredifferent as compared to the last stored set. The processing modulestores the first further modified set of the plurality of sets ofencoded data slices in the DSN memory. Another method of operation isdiscussed in greater detail with reference to FIG. 9.

FIG. 9 is another flowchart illustrating another example of recordingand playback of media. The method begins at step 128 where a processingmodule (e.g., of the distribution unit 96) receives a viewer command(e.g., a set top box request), a viewer ID, and media object identifier(ID). The media object ID is an identifier for the program portion ofthe content 98. For example, media object ID 3017301881018 maycorrespond to the 30 minute 5:30 pm evening news on cable channel 188 onOctober 18. At step 130 the processing module determines if the commandis a record request or a playback request by examining the receivedcommand.

At step 132 the processing module determines if this is the firstrequest to record the media object when the processing module determinesthat the command is the record command. Such a determination may bebased on one or more of reading a vault media object table, reading alocal media object table, and requesting information in a media objecttable from the DS processing unit/distribution unit. The media objecttable may list the identity of the set top boxes that have requested torecord the same media object ID. The processing module determines thatthis is the first request to record the media object when the mediaobject table indicates no other viewers have requested to record thesame media object ID. Note that the processing module may receive aplurality of requests to record a broadcast of data. The method branchesto step 140 to determine updated record operational parameters when theprocessing module determines that this is not the first request torecord the media object.

At step 136 the processing module determines the record operationalparameters when the processing module determines that this is the firstrequest to record the media object (e.g., pillar width n, writethreshold, encoding method, slicing method, encryption method,encryption key, etc.). Such a determination of the record operationalparameters may be based on one or more of a command, a command from thedistribution unit/DS processing unit, an estimated number of storecommands received for the same content indicator, a system performanceindicator, a memory utilization indicator, a policy indicator, a totalpopulation of set top boxes indicator, and a predetermination. Theprocessing module updates the media object table to include a requestingdevice ID and record operational parameters associated with the mediaobject ID.

At step 138 the processing module sends the DS processing unit a storecommand message where the message includes the store command, the mediaobject ID, and the record operational parameters. Additionally, theprocessing module encodes the data using an error coding dispersalstorage function an in accordance with the record operational parametersto produce a plurality of sets of encoded data slices (e.g., EC dataslice sets for each data segment) when the data is broadcast and inresponse to a request of the plurality of requests. The method branchesto step 144 to determine read operational parameters for the requester.

At step 140 the processing module determines updated record operationalparameters. Such a determination may be based on one or more of therecord operational parameters, a command, a command from thedistribution unit/DS processing unit, an estimated number of storecommands received for the same content indicator, a system performanceindicator, a memory utilization indicator, a policy indicator, a totalpopulation of set top boxes indicator, and a predetermination. Forexample, the processing module determines to modify the recordparameters by dropping pillars 3 and 6 and adding pillars 7 and 2. Theprocessing module updates the media object table to include a requestingdevice ID and record operational parameters associated with the mediaobject ID.

At step 142 the processing module sends the DS processing unit a storecommand message where the message includes the store command, the mediaobject ID, and the updated record operational parameters. Additionally,the processing module encodes the data using an error coding dispersalstorage function an in accordance with the updated record operationalparameters to produce a plurality of sets of encoded data slices (e.g.,EC data slice sets for each data segment) when the data is broadcast andin response to a request of the plurality of requests.

At step 144 the processing module generates read operational parametersfor this media object in the form of a unique retrieval matrix for eachof the plurality of requests based on an identity of a requesting deviceand the error coding dispersal storage function to produce a pluralityof unique retrieval matrixes. Alternatively or in addition to, theprocessing module determines the read operational parameters in responseto receiving a playback command as discussed below with reference tostep 148. The processing module generates the unique retrieval matrixbased on at least one of a data identifier, a unique retrieval matrixassociated with at least one other requesting device (e.g., thosealready assigned), a unique retrieval matrix not associated with anyother requesting device (e.g., those not already assigned), and a uniqueretrieval matrix functionality indicator (e.g., an operational statusindicator). Note that the plurality of unique retrieval matrixesincludes a plurality of collectives of pillar identifiers, wherein eachcollective includes pillar identifiers corresponding to at least one ofthe plurality of sets of encoded data slices for retrievingcorresponding encoded data slices. The collective identifies a set ofpillar identifiers for one or more data segments. Further note that anindividual unique retrieval matrix includes one or more of a pillarslist, a segmenting protocol, a pre-slice data manipulation function, aforward error correction encoding function, a slicing pillar width, apost-slice data manipulation function, a write threshold, and a readthreshold. Note that the pillars list includes one of at least onecollective of pillar identifiers associated with less than a slicingpillar width number and at least the read threshold number of aplurality of dispersed storage (DS) units associated with the DSNmemory, and at least one collective of pillar identifiers associatedwith less than the slicing pillar width number and at least the readthreshold number of the plurality of DS units, wherein the at least onecollective of pillar identifiers is unique as compared to every othercollective of pillar identifiers associated with previously determinedunique retrieval matrixes for the same set of the plurality of sets ofencoded data slices. In other words, no other requesting device isassigned the same plurality of collectives of pillar identifiers forthis data. At step 146 the processing module stores the plurality ofsets of encoded data slices and the plurality of unique retrievalmatrixes in a dispersed storage network (DSN) memory as a plurality ofunique copies of the data.

The processing module receives a plurality of playback requests for datafrom a plurality of requesting devices, wherein the data is encoded viaan error coding dispersal storage function to produce a plurality ofsets of encoded data slices which are stored in a dispersed storagenetwork (DSN) memory. At step 148 the processing module determines theread operational parameters for the plurality of playback requests whenthe processing module determines that the command is the playbackcommand. The processing module determines the read operationalparameters by statically or dynamically obtaining a plurality of uniqueretrieval matrixes based on identities of the plurality of requestingdevices. In an example of the static method, the processing moduleretrieves the plurality of unique retrieval matrixes from the DSN memorybased on the identities of the plurality of requesting devices (e.g., alookup of the assignment from a previous playback request or a recordrequest). In an example of the dynamic method, the processing modulegenerates a unique retrieval matrix for each of the plurality ofplayback requests based on one or more of the identities of theplurality of requesting devices, the error coding dispersal storagefunction, a data identifier, a unique retrieval matrix associated withat least one other requesting device, and a unique retrieval matrixfunctionality indicator. Note that the unique retrieval matrix includesone or more of a pillars list, a segmenting protocol, a pre-slice datamanipulation function, a forward error correction encoding function, aslicing pillar width, a post-slice data manipulation function, a writethreshold, and a read threshold. Further note that the pillars listincludes one of at least one collective of pillar identifiers associatedwith less than a slicing pillar width number and at least the readthreshold number of a plurality of dispersed storage (DS) unitsassociated with the DSN memory or at least one collective of pillaridentifiers associated with less than the slicing pillar width numberand at least the read threshold number of the plurality of DS units,wherein the at least one collective of pillar identifiers is unique ascompared to every other collective of pillar identifiers associated withpreviously determined unique retrieval matrixes for the same set of theplurality of sets of encoded data slices.

At step 150 the processing module determines the present (e.g., asequential data segment) plurality of error coded slice namescorresponding to the slices of the data by transforming the data ID(e.g., object name) into the slice names. In addition at step 150 theprocessing module determines DS units based on one or more of the uniqueretrieval matrix pillars list, the data ID, a translation of the data IDto a virtual DSN address, and a lookup of the virtual DSN address tophysical location table. For example, the processing module determinesto retrieve from DS units 3, 4, 5, 6, 7, 11, 12, 13, 15, 16 when theunique retrieval matrix pillars list for a present collective of errorcoded data slices includes the pillars corresponding to DS units 3, 4,5, 6, 7, 11, 12, 13, 15, 16 even when the virtual DSN address tophysical location table includes DS units 1-16 for the data.

At step 152 the processing module sends the DS units retrieve slicecommands and at step 154 receives the EC data slices to retrieve, fromthe DSN memory, a plurality of unique copies of the plurality of sets ofencoded data slices in accordance with the plurality of unique retrievalmatrixes. For example, the processing module retrieves one set of errorcoded data slices, corresponding to a data segment, at a time retrievingthe slices from DS units associated with the pillars of the pillars listfrom the unique retrieval matrix associated with the data segment.Additionally, the processing module may output a unique copy of theplurality of unique copies of the plurality of sets of encoded dataslices to a corresponding requesting device. Additionally, at step 156,the processing module may decode a unique copy of the plurality ofunique copies of the plurality of sets of encoded data slices inaccordance with the error coding dispersal storage function to produce aunique copy of the data. Next, the processing module outputs the uniquecopy of the data to a corresponding requesting device.

Note that the set top box/viewer includes DS processing to convert theEC data slices into the media object for the viewer. Alternatively, theset top box/viewer may process media object data received from theprocessing module of the distribution unit including video or audio orvideo and audio in a real time stream. The set top box/viewer may sendflow control commands (e.g., pause, stop, rewind, fast forward, skipbackwards, skip forwards, etc.) to the distribution unit such that thedistribution unit varies the real time stream in response to thecommands.

FIG. 10 is a schematic block diagram of another embodiment of a mediadistribution system. As illustrated, the system includes a plurality ofviewers 1-V, a plurality of set top boxes 1-V, a video capture unit 158,a DS processing unit 16, a DSN memory 22, and a distribution unit 96.

The distribution unit 96 and the video capture unit 158 may be aportable computing device (e.g., a social networking device, a gamingdevice, a cell phone, a smart phone, a personal digital assistant, adigital music player, a digital video player, a laptop computer, ahandheld computer, a video game controller, and/or any other portabledevice that includes a computing core) and/or a fixed computing device(e.g., a personal computer, a computer server, a cable set-top box, asatellite receiver, a television set, a printer, a fax machine, homeentertainment equipment, a video game console, and/or any type of homeor office computing equipment). The distribution unit 96 and the videocapture unit 158 each includes a computing core 26, one or moreinterfaces 30, 32, and/or 33, and may include a DS processing 34. Asillustrated, the viewer comprises a flat panel television including adisplay and speakers to reproduce the media 100. The viewer mayreproduce the media 100 (e.g., video, audio, pictures, web content)output from the set top box.

The set top box may include the computing core 26 and may include the DSprocessing 34 to receive media slices from the playback DSN memory 194,de-slice, and decode to produce the media 100 for viewing. In addition,the top box 1-V may directly select content 98 (e.g.,broadcast/multicast or on-demand video over cable, satellite and/or theinternet) and/or may select stored content 98 from the DSN memory 22 viathe distribution unit 96. The functions of the set top box and viewermay be integrated together. For example, the viewer (e.g., including settop box functionality) may connect either directly to the DSN memory 22to retrieve media slices 100 or through the distribution unit 96 toreceive media 100. The video capture unit 158 may route portions ofcontent 98 to the DS processing unit 16 for processing and storage tothe DSN memory 22. In an implementation instance, the video capture unit158 and DS processing unit 16 are implemented as an integrated DSprocessing unit 16 to receive content 98 and store slices in the DSNmemory 22.

The set top box sends control commands to the video capture unit 158,the distribution unit 96 and/or DS processing unit. The commands mayinclude one or more of but not limited to record, playback, pause, skipforward, skip backwards, and delete. For example, set top box may send arecord command to the video capture unit 158. In response, video captureunit 158 captures a program (e.g., a portion of the content 98) andcommands the DS processing unit 16 to store the program as data slicesin the DSN memory 22. In another example, the set top box sends aplayback command to the distribution unit 96. In response, thedistribution unit 96 retrieves error coded data slices from the DSNmemory 22 and sends the slices to the set top box.

The video capture unit 158 determines which portion of the content 98 tostore in the DSN memory 22 for subsequent retrieval and consumption byone or more of the set top boxes based on the received commands. Such adetermination may be based on one or more of a command, a command fromthe set top box, a command from the distribution unit 96, and/or apredetermination. For example, set top box 2 may send a record commandto the distribution unit 96 where the record command includes a commandto record the 5:30 pm evening news on cable channel 188 on October 18.The distribution unit 96 processes the record command, which may includesending a store command to the video capture unit 158 and/or DSprocessing unit 16. The video capture unit 158 saves the store commandand executes the store command on October 18 at 5:30 pm. The videocapture unit 158 selects the content 98 from cable channel 188, receivesthe content 98, and sends the content 98 to the DS processing unit 16.The DS processing unit 16 determines the record operational parametersbased on one or more of a command, a command from the distribution unit96, an estimated number of store commands received for the same contentindicator, a system performance indicator, a memory utilizationindicator, a policy indicator, a total population of set top boxesindicator, and a predetermination. Next, the DS unit 16 determines whichDS units 36 to store the EC data slices and sends the EC data slices 100with a store command to the selected DS units 36 of the DSN memory 22for storage therein.

Note that two or more set top boxes may send two or more record commandsfor the same program of the content 98. The DS processing unit 16 mayexecute a record function based on receiving the two or more recordcommands. For example, the DS processing unit 16 may only store EC dataslices produced from content 98 in response to receiving at least onerecord command from at least one set top box. In another example, thedistribution unit 96 sends a record command to the DS processing unit 16based on receiving a first record command for the content 98 and sendsnothing to the DS processing unit 16 when the distribution unit 96receives a second record command for the same content 98. In otherwords, the first record command for a given content portion invokesstoring the content 98 as slices 100 to the DSN memory 22 and any othersubsequent record commands for the same content 98 do not change thestoring of that content 98 as slices 100 in the DSN memory 22. In yetanother example, the distribution unit 96 sends the store command to theDS processing unit 16 based on receiving a first or more record commandsfor the content portion where subsequent record requests may alter therecord operational parameters. For instance, the first record commandfor a given content portion invokes storing the content 98 as EC dataslices to the DSN memory 22 and any other subsequent record commands forthe same content 98 may change the record operational parameters of thatcontent 98. In a specific example, the DS processing unit 16 starts witha 32/26 system and store slices to pillars 1-27 for the first viewer.The DS processing unit 16 continues to store slices but to pillars 2-28when the second viewer requests to record the same content portion. TheDS processing unit 16 changes a slicing pillar width/read threshold froma 32/26 system to a 40/26 system yet storing to at least 32 pillars ofthe 40 to realize storing 32 of 40 pillars in some 76 millioncombinations and still have over 900 thousand combinations to read 26pillars from the 32 stored pillars when even more viewers request torecord the same content portion. The distribution unit 96 and/or DSprocessing unit 16 changes the record operational parameters prior to orduring content capture.

In an example of a record operation, a method begins with a processingmodule of the DS processing unit receiving a first request to store aprogram. The processing module receives (e.g., from the video captureunit 158) the program of the content 98. The processing moduledetermines first error coding dispersal storage function parameters andencodes a data segment of the program in accordance with the first errorcoding dispersal storage function parameters. Such a determination maybe based on one or more of previous parameters, predetermined startingpoint parameters, a command, a set top identifier, and a message. Inaddition, the processing module may send error coded data slices of thedata segment to the DSN memory 22 for storage therein.

The method continues with the step where the processing moduledetermines whether a second request to store the program is received.The processing module encodes a second data segment of the program inaccordance with the first error coding dispersal storage functionparameters when the second request is not received. The processingmodule changes the first error coding dispersal storage functionparameters based on the second request to produce second error codingdispersal storage function parameters when the second request isreceived. The processing module changes the first error coding dispersalstorage function parameters based on the second request includeschanging a post-slice data manipulation function that includes at leastone of an error injection function, a bit dithering function, a bitrotation function, a slice comparison function, a watermark function, ahash function, and a bit swapping function. Next, the processing moduleencodes the second data segment in accordance with the second errorcoding dispersal storage function parameters. In addition, theprocessing module may send error coded data slices of the second datasegment to the DSN memory 22 for storage therein.

In addition, the method may continue with the step where the processingmodule determines whether another request to store the program isreceived, wherein the other request is received, in time, between thefirst and second requests. The processing module determines whether tochange the first error coding dispersal storage function parameters whenthe other request is received. The determination may be based on one ormore of a requester identifier (e.g., which set top box), previousparameters, a performance indicator, predetermined starting pointparameters, a command, and a message. The processing module changes thefirst error coding dispersal storage function parameters based on theother request to produce third error coding dispersal storage functionparameters when the first error coding dispersal storage functionparameters are to be changed. Next, the processing module encodesanother data segment in accordance with the third error coding dispersalstorage function parameters.

Additionally, the processing module may determine a first playback errorcoding dispersal storage function parameter set for a requesting deviceassociated with the first request based on the first error codingdispersal storage function parameters and subsequent changes to thefirst error coding dispersal storage function parameters. The processingmodule determines a second playback error coding dispersal storagefunction parameter set for a second requesting device associated withthe second request based on the second error coding dispersal storagefunction parameters and subsequent changes to the second error codingdispersal storage function parameters. Next, the processing moduleoutputs the first playback error coding dispersal storage functionparameter set to the first requesting device and the processing moduleoutputs the second playback error coding dispersal storage functionparameter set to the second requesting device. Note that the first andsecond error coding dispersal storage function parameters may includeone or more of a pillars list, a segmenting protocol, a pre-slice datamanipulation function, a forward error correction encoding function, aslicing pillar width, a post-slice data manipulation function, a writethreshold, and a read threshold. Note that the pillars list includes atleast one set of pillar identifiers associated with less than a slicingpillar width number or at least the read threshold number of a pluralityof DS units and at least one set of pillar identifiers associated withless than the slicing pillar width number and at least the readthreshold number of the plurality of DS units, wherein the at least oneset of pillar identifiers is unique as compared to every other set ofpillar identifiers associated with previously determined playback errorcoding dispersal storage function parameter set for the program. Forinstance, no other requester (e.g., set top box) utilizes the samepillar combination to retrieve the program.

Note that the encoding method may exclude the use of a unity matrixmultiplier (e.g., which typically results in the encoded data in theform of the data+parity information) such that each slice of each pillaris fully calculated from the encoding algorithm (e.g., the output is amixture of data bits and parity bits). Note that this approach mayimprove the system reliability when at least one of the pillars iswithheld from being stored in accordance with the record operationalparameters and in particular when at minimum a read threshold of pillarsis stored. Further note that this approach may improve the systemsecurity by further disguising the original program data.

The DS processing unit 16, distribution unit 96, and/or storageintegrity processing unit may determine if bit errors have occurred instored slices 100 by examining the contents of slices from time to timeor upon data object retrieval to calculate a cyclic redundancy check(CRC) of the slice content and compare it to a previously stored CRC.Equality of the comparison may indicate no errors and inequality mayindicate at least one bit error. In an embodiment, the storage integrityprocessing unit takes action to correct bit errors when they aredetected. In another embodiment, the storage integrity processing unitdetermines what action to take when bit errors are detected based on oneor more of the read operational parameters, the media object type (e.g.,video, audio, etc) a command, a user vault setting, and/or a systemsetting. For example, the storage integrity processing unit only flagsbit errors (storing in a table or user vault, not correcting the error)when the storage integrity processing unit determines that the mediaobject type is video. Note that the escaping bit errors may bemanifested as impairments to the subsequent video playback and may beunique from one set top box to another set top box when each set top boxreceives the media object where the DS processing receives slices from aunique combination of pillars.

Note that the video capture unit 158, the distribution unit 96 and/or DSprocessing unit 16 may receive a record command after the programportion of the content 98 has started to be received but before it hasall been received (e.g., part way in a real time broadcast). Thedistribution unit 96 and/or DS processing unit 16 may determine the sameor different record operational parameters for a content 98 recording inprogress when an incremental record command for that content 98 isreceived.

In an example of a playback operation, a method begins with a processingmodule of the DS processing unit receiving a plurality of requests toretrieve a stored program that is stored as a plurality of sets ofencoded data slices. The processing module determines playback errorcoding dispersal storage function parameters based on each request toproduce a plurality of determined playback error coding dispersalstorage function parameters for each of the plurality of requests. Thedetermination may be based on one or more of the record operationalparameters, a command, the number of store commands received for thesame program, an estimated number of store commands received for thesame content indicator, which combinations of pillars have already beenassigned (e.g., the read operational parameters of other viewers), asystem performance indicator, a memory utilization indicator, a pillaravailability indicator, a policy indicator, a total population of settop boxes indicator, and/or a predetermination.

The processing module determines the DS units 36 based on a program IDand/or the playback error coding dispersal storage function parameters.The processing module processes a first one of the plurality of requestsby retrieving a first set of the plurality of sets of encoded dataslices from the DS units 36 based on a first one of the plurality ofdetermined playback error coding dispersal storage function parameters.Note that the playback error coding dispersal storage functionparameters includes one or more of a pillars list, a segmentingprotocol, a pre-slice data manipulation function, a forward errorcorrection encoding function, a slicing pillar width, a write threshold,a read threshold, and a post-slice data manipulation function. Thepost-slice data manipulation function includes at least one of an errorinjection function, a bit dithering function, a bit rotation function, aslice comparison function, a watermark function, a hash function, and abit swapping function. The pillars list includes one of at least one setof pillar identifiers associated with less than a slicing pillar widthnumber and at least the read threshold number of a plurality of DSunits, and at least one set of pillar identifiers associated with lessthan the slicing pillar width number and at least the read thresholdnumber of the plurality of DS units, wherein the at least one set ofpillar identifiers is unique as compared to every other set of pillaridentifiers associated with previously determined playback error codingdispersal storage function parameter set for the recovered data.

The method continues with the step where the processing module outputsthe first set of the plurality of sets of encoded data slices to a firstrequesting device associated with the first one of the plurality ofrequests. In an instance of outputting, the processing module decodesthe first set of the plurality of sets of encoded data slices based onthe first one of the plurality of determined playback error codingdispersal storage function parameters to produce first recovered dataand output the first recovered data to the first requesting deviceassociated with the first one of the plurality of requests.

The processing module processes a second one of the plurality ofrequests by retrieving a second set of the plurality of sets of encodeddata slices based on a second one of the plurality of determinedplayback error coding dispersal storage function parameters. Theprocessing module outputs the second set of the plurality of sets ofencoded data slices to a second requesting device associated with thesecond one of the plurality of requests. In an instance of outputting,the processing module decodes the second set of the plurality of sets ofencoded data slices based on the second one of the plurality ofdetermined playback error coding dispersal storage function parametersto produce second recovered data and outputs the second recovered datato the second requesting device associated with the second one of theplurality of requests.

FIG. 11 is a schematic block diagram of another embodiment of a mediadistribution system. As illustrated, the system includes a plurality ofviewers 1-V, a plurality of set top boxes 1-V, a video capture unit 158,a DS processing unit 16, a DSN memory 22, and a distribution unit 96.The plurality of viewers 1-V, the plurality of set top boxes 1-V, thevideo capture unit 158, the DS processing unit 16, the DSN memory 22,and the distribution unit 96 operate in accordance with, but not limitedto, the operations as described previously with reference to FIGS. 6-10.

In an example of operation, a processing module (e.g., of thedistribution unit) receives a playback request from a requesting deviceto access data stored as encoded data slices in the DSN memory 22. Theprocessing module determines playback operational parameters utilizing astatic method or a dynamic method. The processing module determinesplayback operational parameters by retrieving the playback operationalparameters from the DSN memory 22 when utilizing the static method. Theprocessing module determines playback operational parameters bygenerating new playback operational parameters when utilizing thedynamic method as previously discussed. The processing module retrievesencoded data slices of the data in accordance with the playbackoperational parameters (e.g., retrieving slices from DS units alignedwith the playback operational parameters). Note that the processingmodule may utilize a first collective of playback operational parametersto attempt to retrieve and decode the encoded data slices from the DSunits 36. The processing module determines if the slice retrieval anddecoding is successful. The processing unit utilizes a second collectiveof the playback operational parameters to attempt to retrieve and decodethe slices 100 when the processing module determines that the attemptwith the first collective is not successful. The processing modulecontinues this process until all the assigned collectives of playbackoperational parameters have been tried.

The processing module may generate at least one additional collective ofplayback operational parameters when the processing module determinesthat all of the previously assigned collectives of playback operationalparameters have been tried without success (e.g., failure of decodingthe data segment from available slices). For example, the processingmodule generates at least one additional collective of playbackoperational parameters that is unique with respect to all of the othercollectives of playback operational parameters assigned to otherrequesting devices. In an instance, the requesting device may beassigned four unique combinations of read pillars to utilize to retrieveand decode slices 100. In another example, the processing modulegenerates at least one additional collective of playback operationalparameters that is not unique with respect to all of the othercollectives of playback operational parameters assigned to otherrequesting devices. In an instance, the requesting device may beassigned three unique combinations of read pillars and one that isalready assigned to another requesting device to utilize to retrieve anddecode slices 100. The processing module retrieves, de-slices, anddecodes the encoded data slices to produce the media object 100 when asuccessful combination of read operational parameters is utilized. Theprocessing module sends the slices and/or the media object 100 to therequesting device (e.g., a set top box).

FIG. 12 is another flowchart illustrating another example of recordingand playback of media. The method of steps 160-178 operates aspreviously discussed with reference to step 128-146 of FIG. 9.

The processing module (e.g., of a distribution unit 96) receives aplurality of playback requests for data from a plurality of requestingdevices, wherein the data is encoded via an error coding dispersalstorage function to produce a plurality of sets of encoded data sliceswhich are stored in a dispersed storage network (DSN) memory. At step180 the processing module determines the read operational parameters forthe plurality of playback requests when the processing module determinesthat the command is the playback command. The processing moduledetermines the read operational parameters by obtaining a plurality ofunique retrieval matrixes based on identities of the plurality ofrequesting devices. The processing module obtains the plurality ofunique retrieval matrixes by one of a static method or a dynamic method.In an example of the static method, the processing module retrieves theplurality of unique retrieval matrixes from the DSN memory based on theidentities of the plurality of requesting devices (e.g., a lookup of theassignment from a previous playback request or a record request). In anexample of the dynamic method, the processing module generates a uniqueretrieval matrix for each of the plurality of playback requests based onone or more of a failed unique retrieval matrix, the identities of theplurality of requesting devices, the error coding dispersal storagefunction, a data identifier, a unique retrieval matrix associated withat least one other requesting device, and a unique retrieval matrixfunctionality indicator. Note that the unique retrieval matrix includesone or more of a pillars list, a segmenting protocol, a pre-slice datamanipulation function, a forward error correction encoding function, aslicing pillar width, a post-slice data manipulation function, a writethreshold, and a read threshold. Further note that the pillars listincludes one of at least one collective of pillar identifiers associatedwith less than a slicing pillar width number and at least the readthreshold number of a plurality of dispersed storage (DS) unitsassociated with the DSN memory or at least one collective of pillaridentifiers associated with less than the slicing pillar width numberand at least the read threshold number of the plurality of DS units,wherein the at least one collective of pillar identifiers is unique ascompared to every other collective of pillar identifiers associated withpreviously determined unique retrieval matrixes for the same set of theplurality of sets of encoded data slices.

At step 182 the processing module determines the present (e.g., asequential data segment) plurality of error coded slice namescorresponding to the slices of the data by transforming the data ID(e.g., object name) into the slice names. In addition at step 182 theprocessing module determines DS units based on one or more of the uniqueretrieval matrix pillars list, the data ID, a translation of the data IDto a virtual DSN address, and a lookup of the virtual DSN address tophysical location table. For example, the processing module determinesto retrieve from DS units 3, 4, 5, 6, 7, 11, 12, 13, 15, 16 when theunique retrieval matrix pillars list for first collective of error codeddata slices includes the pillars corresponding to DS units 3, 4, 5, 6,7, 11, 12, 13, 15, 16 even when the virtual DSN address to physicallocation table includes DS units 1-16 for the data.

At step 184 the processing module sends the DS units retrieve slicecommands and receives the EC data slices from the DSN memory, aplurality of unique copies of the plurality of sets of encoded dataslices in accordance with the plurality of unique retrieval matrixes.For example, the processing module retrieves one set of error coded dataslices, corresponding to a data segment, at a time retrieving the slicesfrom DS units associated with the pillars of the pillars list from thefirst unique retrieval matrix associated with the data segment.Additionally, the processing module may output a unique copy of theplurality of unique copies of the plurality of sets of encoded dataslices to a corresponding requesting device.

At step 186 the processing module attempts to decode a unique copy ofthe plurality of unique copies of the plurality of sets of encoded dataslices in accordance with the error coding dispersal storage function toproduce a unique copy of the data. Additionally, the processing moduledetermines if the unique copy was successfully decoded. The processingmodule determines that the retrieval is not successful when fewer than aread threshold number of slices are received for any data segment. Atstep 190 the processing module determines a different combination ofread operational parameters (e.g., a different unique retrieval matrix)when the distribution unit determines that the required data segments ofthe media object have not been successfully recreated (e.g., from afailure such as the DSN memory, network, etc.). Note that the differentcombination may have already been assigned as retrieved from DSN memory.The processing module may assign at least one new combination of readoperational parameters for the requester when the processing module hasattempted to utilize all the currently assigned combinations of the readoperational parameters without success. In an instance, the processingmodule assigns the at least one new combination of read operationalparameters that is unique from all of the other previously assignedcombinations of read operational parameters for all of the requestingdevices that have sent the record and/or playback command for the samemedia object. The method repeats back to step 182 to make anotherretrieval attempt utilizing the different unique retrieval matrix,

At step 188 the processing module sends the media object to therequester that requested the playback. The media object may be sentwhole (all at once as a file) or as a stream. The stream may comprisethe media object and/or the slices. In an embodiment, the set topbox/viewer includes DS processing to convert the slices into the mediaobject for the viewer. In another embodiment, the set top box/viewer mayprocess the media object sent from the distribution unit including videoor audio or video and audio in a real time stream. The set topbox/viewer may send flow control commands (e.g., pause, stop, rewind,fast forward, skip backwards, skip forwards, etc.) to the distributionunit such that the distribution unit varies the real time stream inresponse to the commands.

FIG. 13 is a schematic block diagram of an embodiment of a mediadistribution system. As illustrated, the system includes a plurality ofviewers 1-V, a plurality of set top boxes 1-V, a DS processing unit 16,an ingest DSN memory 192, a playback DSN memory 194, and a distributionunit 96.

The distribution unit 96 may be a portable computing device (e.g., asocial networking device, a gaming device, a cell phone, a smart phone,a personal digital assistant, a digital music player, a digital videoplayer, a laptop computer, a handheld computer, a video game controller,and/or any other portable device that includes a computing core) and/ora fixed computing device (e.g., a personal computer, a computer server,a cable set-top box, a satellite receiver, a television set, a printer,a fax machine, home entertainment equipment, a video game console,and/or any type of home or office computing equipment). The distributionunit 96 includes a computing core 26, one or more interfaces 30, 32,and/or 33, and may include a DS processing 34.

As illustrated, the viewer may comprise a flat panel television and mayinclude a display and speakers to reproduce the media 100. The viewermay reproduce the media 100 (e.g., video, audio, pictures, web content)output from the set top box.

The set top box includes the computing core 26 and includes the DSprocessing 34 to receive media slices from the playback DSN memory 194,de-slice, and decode to produce the media 100 for viewing. In addition,the top box 1-V may directly select content 98 (e.g.,broadcast/multicast or on-demand video over cable, satellite and/or theinternet) and/or may select stored content 98 from the playback DSNmemory 194 system via the distribution unit 96. The functions of the settop box and viewer may be integrated together. For example, the viewer(e.g., including set top box functionality) may connect either directlyto the playback DSN memory 194 to retrieve media slices 100 or throughthe distribution unit 96 to receive media 100.

The set top box sends control commands to the distribution unit 96and/or DS processing unit 16 to control the DS processing unit 16 and/ordistribution unit 96. The commands may include one or more of but notlimited to record, playback, pause, skip forward, skip backwards, anddelete. For example, set top box may send a record command to the DSprocessing unit 16. In response, the DS processing unit 16 stores aportion of the content 98 in the ingest DSN memory 192. The set top boxmay send a playback command to the distribution unit 96. In response,the distribution unit 96 and/or set top box retrieves a portion of thecontent 98 from the playback DSN memory 194 and sends the portion to theviewer and/or set top box.

To facilitate recording of content 98, the DS processing unit 16determines which portion (e.g., a media program) of the content 98 tostore in the ingest DSN memory 192. The determination may be based onone or more of a command, a command from the set top box, a command fromthe distribution unit 96, and/or a predetermination. For example, settop box 2 may send a record command to the distribution unit 96 wherethe record command includes a command to record the 5:30 pm evening newson cable channel 188 on October 18. The distribution unit 96 processesthe record command which may include sending a store command to the DSprocessing unit 16. Next, the DS processing unit 16 saves the storecommand and executes the store command on October 18 at 5:30 pm. The DSprocessing unit 16 selects the content 98 from cable channel 188,receives the content 98, determines record operational parameters (e.g.,pillar width n, write threshold, encoding method, slicing method,encryption method, etc.), creates a plurality of groups of sets ofencoded data slices from the content 98 in accordance with the recordoperational parameters, and sends the plurality of groups of sets ofencoded data slices to the ingest DSN memory 192 for storage. Note thata group of sets of the plurality of groups of sets of encoded dataslices corresponds to a time window of the stored program and a set ofencoded data slices of the group of sets of the plurality of groups ofsets of encoded data slices corresponds to a data segment of the timewindow. The DS processing unit 16 determines the record operationalparameters based on one or more of a command, a command from thedistribution unit 96, an estimated number of store commands received forthe same content indicator, a system performance indicator, a memoryutilization indicator, a policy indicator, a total population of set topboxes indicator, and a predetermination.

Multiple set top boxes may send a record command for the same program.The DS processing unit 16 may only store slices created from content inresponse to receiving at least one record command from at least one settop box. The distribution unit 96 determines if it has received recordcommands for the same content (e.g., check a media object table ofpending record operations) and processes the record commands inaccordance with the determination. The distribution unit 96 sends thestore command to the DS processing unit 16 based on receiving a firstrecord command for the content 98 and sends nothing to the DS processingunit 16 when the distribution unit 96 receives a second record commandfor the same content 98 as the first record command. In other words, thefirst record command for a given content portion invokes storing thecontent 98 as the plurality of groups of sets of encoded data slices inthe ingest DSN memory 192 and any other subsequent record commands forthe same content 98 do not change the storing of that content 98 in theingest DSN memory 192.

Alternatively, the distribution unit 96 sends the store command to theDS processing unit 16 based on receiving a first record command for thecontent 98 and sends another store command to the DS processing unit 16when the distribution unit 96 receives a second (or more) record commandfor the same content as the first record command. The DS processing unit16 may determine different record operational parameters based onreceiving two or more store commands for the same content 98. Thedetermination may be based on one or more of a command, a command fromthe distribution unit 96, the number of store commands received for thesame content 98, a system performance indicator, a memory utilizationindicator, a policy indicator, a total population of set top boxesindicator, and/or a predetermination. Note that the distribution unit 96and/or DS processing unit 16 may receive a record/store command afterthe content 98 has been started to be received but before it has allbeen received (e.g., part way in a real time broadcast). Thedistribution unit 96 and/or DS processing unit 16 may determine the sameor different record operational parameters for a content 98 recording inprogress when an incremental record command for that content 98 isreceived.

The distribution unit 96 processes the record command (e.g., from theviewer/set top box) and may include determining read operationalparameters for the viewer for this content 98 (e.g., pillar width n ofthe playback DSN memory 194, what portion of the slices of the mediaobject 100 to have current on the playback DSN memory 194, whichparticular pillars are allowed to read, read threshold, decoding method,de-slicing method, decryption method, etc.). For example, the readoperational parameters may specify that at maximum ten seconds of themedia object 100 may be saved in the playback DSN memory 194 per set topbox. In an instance, the distribution unit 96 may make the determinationwhen the distribution unit 96 receives the record command. In anotherinstance, the distribution unit 96 may make the determination when thedistribution unit 96 receives the playback command. Such a determinationmay be based on one or more of a current playback position (e.g., howfar along in the playback), a command, the number of store commandsreceived for the same content 98, an estimated number of store commandsreceived for the same content indicator, the read operational parametersof other viewers, a system performance indicator, a memory utilizationindicator, a playback DSN memory availability indicator, a policyindicator, a total population of set top boxes indicator, and apredetermination. For example, set top box 1 may be assigned readoperational parameters to read from pillars 1-10 and set top box 2 maybe assigned read operational parameters to read from pillars 3-12 whenthe playback DSN memory 194 has 16 pillars and a read threshold of 10.The read operational parameters may be utilized in the DS processing(e.g., in the distribution unit 96 and/or the set top box/viewer) tosubsequently convert the stored slices 100 from the allowed read pillarsinto the desired portion of the media content 100.

The viewer/set top box sends a playback command to the distribution unit96 to invoke the retrieval and conversion of the plurality of groups ofsets of encoded data slices from the playback DSN memory 194 into themedia object 100. The distribution unit 96 determines if the readoperational parameters have been determined for this viewer/set top boxbased on a lookup (e.g., a media object table and/or user vault). Thedistribution unit 96 determines the read operational parameters by thelookup when the distribution unit 96 determines that the readoperational parameters have been previously determined for thisviewer/set top box (e.g., they may have been determined by thedistribution unit 96 in response to receiving a record command). Thedistribution unit 96 determines the read operational parameters when thedistribution unit 96 determines that the read operational parametershave not been previously determined for this viewer/set top box. Theread operational parameters determination may be based on one or more ofthe record operational parameters, a command, the number of storecommands received for the same content 98, an estimated number of storecommands received for the same content indicator, the read operationalparameters of other viewers, a playback DSN memory performanceindicator, a memory utilization indicator, a pillar availabilityindicator, a policy indicator, a total population of set top boxesindicator, and a predetermination.

The distribution unit 96 determines the playback DSN memory DS units 36based on the media object ID and/or the read operational parameters. Thedistribution unit 96 determines the ingest DSN memory 192 DS units 36based on the media object ID and/or the record operational parameters.The distribution unit 96 sends a replicate command to the playback DSNmemory 194 DS units 36 to replicate slices of the media object 100 fromthe ingest DSN memory 192 DS units 36 in accordance with the readoperational parameters. For example, the playback DSN memory 194 DSunits 36 maintain ten seconds (e.g., with respect to real time video) ofreplicated slices of the media object 100 from the ingest DSN memory 192DS units 36 by sending a series of slice retrieval commands to theingest DSN memory 192 DS units 36. The playback DSN memory 194 DS units36 receive the replicated slices from the ingest DSN memory 192 DS units36 and store the replicated slices in the playback DSN memory 194 DSunits 36. Note that while slices of the entire media object 100 may bestored in the ingest DSN memory 192, only a small portion of the slices100 of the media object 100 unique to the particular viewer/set top box(e.g., the ten second window preceding the play point) may be present inthe playback DSN memory 194 at any one time. Further note that the smallportion of slices of the media object 100 are only present in theplayback DSN memory 194 in response to a playback command from theviewer/set top box. Yet further note that each viewer/set top box mayhave its own unique corresponding slices 100 in the playback DSN memory194.

A DS processing 34 processes a playback command. For example, theprocessing module of the distribution unit 96 may process the playbackcommand. The method begins with the step where the processing modulereceives a plurality of playback requests (e.g., from multiple set topboxes) for a stored program, wherein the stored program is stored in adispersed storage network (DSN) memory (e.g., the ingest DSN memory 192)as a plurality of groups of sets of encoded data slices, wherein a groupof sets of the plurality of groups of sets of encoded data slicescorresponds to a time window of the stored program and a set of encodeddata slices of the group of sets of the plurality of groups of sets ofencoded data slices corresponds to a data segment of the time window.

The method continues where the processing module stores a first group ofthe plurality of groups of sets of encoded data slices in a playback DSNmemory to produce a first buffered group in response to each of theplurality of playback requests. The processing module stores the firstgroup in a portion of the playback DSN memory 194 allocated to therequesting device. Alternatively, or in addition to, the processingmodule may decode the first group of the plurality of groups of sets ofencoded data slices in accordance with an error coding dispersal storagefunction to produce a recaptured first time window. Next, the processingmodule encodes the recaptured first time window in accordance with asecond error coding dispersal storage function to produce a re-encodedfirst group. Next, the processing module stores the re-encoded firstgroup in the playback DSN memory to produce the first buffered group. Inother words, the processing module transcodes the slices.

The method continues where the processing module outputs the firstbuffered group to a requesting device (e.g., a set top box)corresponding to the each of the plurality of playback requests.Alternatively, or in addition to, the processing module may decode thefirst group of the plurality of groups of sets of encoded data slices inaccordance with an error coding dispersal storage function to produce afirst time window of multimedia data and output the first time window ofmultimedia data to the requesting device.

The method continues where the processing module stores a second groupof the plurality of groups of sets of encoded data slices in theplayback DSN memory to produce a second buffered group. The processingmodule stores the second group in the portion of the playback DSN memory194 allocated to the requesting device. Note that the processing modulemay store the second group of the plurality of groups of sets of encodeddata slices by at least one of overwriting the first buffered group anddeleting the first buffered group. In other words, the size of thebuffer is maintained. The method continues where the processing moduleoutputs the second buffered group to the requesting device.

The processing module may utilize an alternative method to process aplayback command. For example, the method begins where the processingmodule requests transfer of a first group of a plurality of groups ofsets of encoded data slices of the stored program from the dispersedstorage network (DSN) memory (e.g., the ingest DSN memory 192) to theplayback DSN memory 194, wherein the stored program is stored in the DSNmemory as the plurality of groups of sets of encoded data slices,wherein a group of sets of the plurality of groups of sets of encodeddata slices corresponds to a time window of the stored program and a setof encoded data slices of the group of sets of the plurality of groupsof sets of encoded data slices corresponds to a data segment of the timewindow. Alternatively, or in addition to, the processing module requeststransfer of the first group by decoding the first group of the pluralityof groups of sets of encoded data slices in accordance with an errorcoding dispersal storage function to produce a recaptured first timewindow. Next, the processing module encodes the recaptured first timewindow in accordance with a second error coding dispersal storagefunction to produce a re-encoded first group. Next, the processingmodule stores the re-encoded first group in the playback DSN memory toproduce the first buffered group.

The method continues where the processing module retrieves the firstgroup from the playback DSN memory. Alternatively, or in addition to,the processing module may decode the first group in accordance with anerror coding dispersal storage function to produce multimedia data(e.g., for consumption by the viewer). The method continues with thestep where the processing module requests transfer of a second group ofthe plurality of groups of sets of encoded data slices from the ingestDSN memory 192 to the playback DSN memory 194 to produce a second group.Note that the processing module may request transfer of the second groupby at least one of overwriting the first group and deleting the firstgroup. The method continues where the processing module retrieves thesecond group from the playback DSN memory (e.g., for consumption by theviewer).

In addition to the playback methods previously discussed, the processingmodule may receive other commands to affect the processing of theprogram. For example, the processing module pauses the storing of thefirst and second groups for the particular requesting device and flags amost recent outputted group to the particular requesting device toproduce a most recent group indicator in response to receiving a pausecommand from a particular requesting device. In another example, theprocessing module resumes the storing of the first and second groups forthe particular requesting device in accordance with the most recentgroup indicator in response to receiving a play command from aparticular requesting device. In another example, the processing moduletraverses ordering of the storing of the first and second groups for theparticular requesting device in response to receiving a rewind commandfrom a particular requesting device. In another example, the processingmodule skips the storing of the first group or the second group for theparticular requesting device, stores a third group of the plurality ofgroups of sets of encoded data slices in the playback DSN memory toproduce a third buffered group, and outputs the third buffered group tothe requesting device in response to receiving a fast forward commandfrom a particular requesting device.

FIG. 14 is a schematic block diagram of an embodiment of a mediadistribution system. The system includes a plurality of viewers 1-V, aplurality of set top boxes 1-V, an ingest DS processing unit 196, aningest DSN memory 192, a playback DS processing unit 198, a playback DSNmemory 194, and a distribution unit 96.

The viewer may reproduce the media 100 (e.g., video, audio, pictures,web content) output from the set top box. For example, the viewer maycomprise a flat panel television and may include a display and speakersto reproduce the media 100.

The set top box may select content 98 (e.g., broadcast/multicast oron-demand video over cable, satellite and/or the internet) and/or storedcontent 98 from the distributed storage system via the distribution unit96. The set top box may comprise the computing core of FIG. 2 and in anembodiment may include the DS processing to receive media slices 100from the playback DSN memory 194, de-slice, and decode to produce themedia 100 for viewing. In another embodiment, the set top box receivesmedia from the distribution unit 96 (e.g., the distribution unit 96utilizes the playback DS processing unit 198 to retrieve media slices,de-slices, and decodes to produce the media 100 for distribution to theset top box and viewer).

In another embodiment, the functions of the set top box and viewer areintegrated together. For example, the viewer may connect either directlyto the playback DSN memory 194 to retrieve media slices 100 or throughthe distribution unit 96 to receive media 100.

The set top box sends control commands to the distribution unit 96,playback DS processing unit 198, and/or ingest DS processing unit 196 toinvoke media recording and playback. The commands may include, but arenot limited to record, playback, pause, skip forward, skip backwards,and delete. For example, the ingest DS processing unit 196 may store aportion of the content 98 in the ingest DSN memory 192 in response to arecord command and the distribution unit 96/playback DS processing unit198 and/or set top box may retrieve a portion of the content 98 from theplayback DSN memory 198 and send it to the viewer/set top box inresponse to receiving a playback command.

The ingest DS processing unit 196 determines which portion of thecontent 98 to store in the ingest DSN memory 196 for subsequent transferto the playback DSN memory 194, retrieval and consumption by one or moreof the set top boxes based on the received commands. The determinationmay be based on one or more of a command, a command from the set topbox, a command from the distribution unit 96, and/or a predetermination.For example, set top box 2 may send a record command to the distributionunit 96 where the record command includes a command to record the 5:30pm evening news on cable channel 188 on October 18. The distributionunit 96 processes the record command which may include sending a storecommand to the ingest DS processing unit 196. The ingest DS processingunit 196 saves the store command and executes the store command onOctober 18 at 5:30 pm. The ingest DS processing unit 196 selects thecontent 98 from cable channel 188, receives the content 98, determinesthe record operational parameters (e.g., pillar width n, writethreshold, encoding method, slicing method, encryption method, etc.),creates EC data slices 100 from the content 98 in accordance with therecord operational parameters, determines which DS units 36 to store theEC data slices 100, and sends the EC data slices 100 with a storecommand to the selected DS units 36 of the ingest DSN memory 192 forstorage.

The distribution unit 96 and/or ingest DS processing unit 196 determinesthe record operational parameters based on one or more of a command, acommand from the distribution unit 96, an estimated number of storecommands received for the same content indicator, a system performanceindicator, a memory utilization indicator, a policy indicator, a totalpopulation of set top boxes indicator, and/or a predetermination.

Note that multiple set top boxes may send the record command for thesame content 98. In an embodiment, the ingest DS processing unit 196 mayonly store slices 100 created from content 98 in response to receivingat least one record command from at least one set top box. Thedistribution unit 96 determines if it has received record commands forthe same content 98 (e.g., check a media object table of pending recordoperations) and processes the record commands in accordance with thedetermination. In an embodiment, the distribution unit 96 sends thestore command to the ingest DS processing unit 196 (as discussedpreviously) based on receiving a first record command for the content 98and sends nothing to the ingest DS processing unit 196 when thedistribution unit 96 receives a second record command for the samecontent 98 as the first record command. In other words, the first recordcommand for a given content portion invokes storing the content 98 asslices 100 to the ingest DSN memory 192 and any other subsequent recordcommands for the same content 98 do not change the storing of thatcontent 98 as slices 100 in the ingest DSN memory 192.

In an example of operation, the distribution unit 96 sends the storecommand to the ingest DS processing unit 196 based on receiving a firstrecord command for the content 98 and sends another store command to theingest DS processing unit 196 when the distribution unit 96 receives asecond (or more) record command for the same content 98 as the firstrecord command. The distribution unit 96 and/or ingest DS processingunit 196 determines different record operational parameters based onreceiving two or more store commands for the same content 98. Such adetermination may be based on one or more of a command, a command fromthe distribution unit 96, the number of store commands received for thesame content 98, a system performance indicator, a memory utilizationindicator, a policy indicator, a total population of set top boxesindicator, and a predetermination.

In a mode of operation, the distribution unit 96 and/or the ingest DSprocessing unit 196 may receive a record/store command after the content98 has been started to be received but before it has all been received(e.g., part way in a real time broadcast). The distribution unit 96and/or the ingest DS processing unit 196 determine the same or differentrecord operational parameters for a content recording in progress whenan incremental record command for that content 98 is received.

The distribution unit 96 processes the record command (e.g., from theviewer/set top box) and includes determining read operational parametersfor the viewer for this content (e.g., pillar width n of the playbackDSN memory 194, what portion of the slices of the media object 100 tohave current on the playback DSN memory 194, which particular pillarsare allowed to read, read threshold, decoding method, de-slicing method,decryption method, etc.). For example, the read operational parametersmay specify that at maximum ten seconds of the media object 100 may besaved in the playback DSN memory 194. In an instance, the distributionunit 96 may make the determination when the distribution unit 96receives the record command. In another instance, the distribution unit96 may make the determination when the distribution unit 96 receives theplayback command. Such a determination may be based on one or more of acurrent playback position (e.g., how far along in the playback), acommand, the number of store commands received for the same content 98,an estimated number of store commands received for the same contentindicator, the read operational parameters of other viewers, a systemperformance indicator, a memory utilization indicator, a playback DSNmemory 194 availability indicator, a policy indicator, a totalpopulation of set top boxes indicator, and a predetermination. Forexample, set top box 1 may be assigned read operational parameters toread from pillars 1-10 and set top box 2 may be assigned readoperational parameters to read from pillars 3-12 when the playback DSNmemory 194 has 16 pillars and a read threshold of 10. The readoperational parameters may be utilized in the playback DS processing(e.g., or in the distribution unit and/or the set top box/viewer) tosubsequently convert the stored slices 100 from the allowed read pillarsinto the desired portion of the media content 100.

The viewer/set top box sends a playback command to the distribution unit96 to invoke the retrieval and conversion of stored slices 100 from theplayback DSN memory 194 into the media object 100. The distribution unit96 determines if the read operational parameters have been determinedfor this viewer/set top box based on a lookup (e.g., a media objecttable and/or user vault). The distribution unit 96 determines the readoperational parameters by the lookup when the distribution unit 96determines that the read operational parameters have been previouslydetermined for this viewer/set top box (e.g., they may have beendetermined by the distribution unit 96 in response to receiving a recordcommand). The distribution unit 96 determines the read operationalparameters when the distribution unit 96 determines that the readoperational parameters have not been previously determined for thisviewer/set top box. The read operational parameters determination may bebased on one or more of the record operational parameters, a command,the number of store commands received for the same content 98, anestimated number of store commands received for the same contentindicator, the read operational parameters of other viewers, a playbackDSN memory performance indicator, a memory utilization indicator, apillar availability indicator, a policy indicator, a total population ofset top boxes indicator, and a predetermination.

The distribution unit 96 determines the playback DSN memory 194 DS units36 based on the media object ID and/or the read operational parameters.The distribution unit 96 determines the ingest DSN memory 192 DS units36 based on the media object ID and/or the record operationalparameters. The distribution unit 96 and/or playback DS processing unit198 sends a replicate command to the playback DSN memory 194 DS units 36to replicate slices of the media object 100 from the ingest DSN memory192 DS units 36 in accordance with the read operational parameters. Forexample, the playback DSN memory 194 DS units 36 maintain ten seconds(e.g., with respect to real time video) of replicated slices of themedia object 100 from the ingest DSN memory 192 DS units 36 by sending aseries of slice retrieval commands to the ingest DSN memory 192 DS units36. The playback DSN memory 194 DS units 36 receive the replicatedslices 100 from the ingest DSN memory 192 DS units 36 and stores thereplicated slices 100 in the playback DSN memory 194 DS units 36. Notethat while slices of the entire media object 100 may be stored in theingest DSN memory 192, only a small portion of the slices of the mediaobject 100 unique to the particular viewer/set top box (e.g., the tensecond window preceding the play point) may be present in the playbackDSN memory 194 at any one time. Further note that the small portion ofslices of the media object 100 are only present in the playback DSNmemory 194 in response to a playback command from the viewer/set topbox. Yet further note that each viewer/set top box may have its ownunique corresponding slices in the playback DSN memory 194.

The playback DS processing unit 194 (or distribution unit 96 and/or settop box) retrieves, de-slices, and decodes the replicated slices 100from the playback DSN memory 194 DS units 36 in accordance with the readoperational parameters to produce a media object stream. Thedistribution unit 96 may delete the replicated slices 100 that were justretrieved from the playback DSN memory 194 DS units 36 and the playbackDSN memory 194 DS units 36 may continue to retrieve more replicatedslices 100 from the ingest DSN memory 192 DS units 36 in accordance withthe read operational parameters (e.g., to maintain ten seconds of realtime media object slices 100). The playback DS processing 198 sends themedia object 100 (batch or stream) to the distribution unit 96. Thedistribution unit 96 sends the media object stream 100 to the viewer/settop box.

As may be used herein, the terms “substantially” and “approximately”provides an industry-accepted tolerance for its corresponding termand/or relativity between items. Such an industry-accepted toleranceranges from less than one percent to fifty percent and corresponds to,but is not limited to, component values, integrated circuit processvariations, temperature variations, rise and fall times, and/or thermalnoise. Such relativity between items ranges from a difference of a fewpercent to magnitude differences. As may also be used herein, theterm(s) “operably coupled to”, “coupled to”, and/or “coupling” includesdirect coupling between items and/or indirect coupling between items viaan intervening item (e.g., an item includes, but is not limited to, acomponent, an element, a circuit, and/or a module) where, for indirectcoupling, the intervening item does not modify the information of asignal but may adjust its current level, voltage level, and/or powerlevel. As may further be used herein, inferred coupling (i.e., where oneelement is coupled to another element by inference) includes direct andindirect coupling between two items in the same manner as “coupled to”.As may even further be used herein, the term “operable to” or “operablycoupled to” indicates that an item includes one or more of powerconnections, input(s), output(s), etc., to perform, when activated, oneor more its corresponding functions and may further include inferredcoupling to one or more other items. As may still further be usedherein, the term “associated with”, includes direct and/or indirectcoupling of separate items and/or one item being embedded within anotheritem. As may be used herein, the term “compares favorably”, indicatesthat a comparison between two or more items, signals, etc., provides adesired relationship. For example, when the desired relationship is thatsignal 1 has a greater magnitude than signal 2, a favorable comparisonmay be achieved when the magnitude of signal 1 is greater than that ofsignal 2 or when the magnitude of signal 2 is less than that of signal1.

While the transistors in the above described figure(s) is/are shown asfield effect transistors (FETs), as one of ordinary skill in the artwill appreciate, the transistors may be implemented using any type oftransistor structure including, but not limited to, bipolar, metal oxidesemiconductor field effect transistors (MOSFET), N-well transistors,P-well transistors, enhancement mode, depletion mode, and zero voltagethreshold (VT) transistors.

The present invention has also been described above with the aid ofmethod steps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claimed invention.

The present invention has been described, at least in part, in terms ofone or more embodiments. An embodiment of the present invention is usedherein to illustrate the present invention, an aspect thereof, a featurethereof, a concept thereof, and/or an example thereof. A physicalembodiment of an apparatus, an article of manufacture, a machine, and/orof a process that embodies the present invention may include one or moreof the aspects, features, concepts, examples, etc. described withreference to one or more of the embodiments discussed herein.

The present invention has been described above with the aid offunctional building blocks illustrating the performance of certainsignificant functions. The boundaries of these functional buildingblocks have been arbitrarily defined for convenience of description.Alternate boundaries could be defined as long as the certain significantfunctions are appropriately performed. Similarly, flow diagram blocksmay also have been arbitrarily defined herein to illustrate certainsignificant functionality. To the extent used, the flow diagram blockboundaries and sequence could have been defined otherwise and stillperform the certain significant functionality. Such alternatedefinitions of both functional building blocks and flow diagram blocksand sequences are thus within the scope and spirit of the claimedinvention. One of average skill in the art will also recognize that thefunctional building blocks, and other illustrative blocks, modules andcomponents herein, can be implemented as illustrated or by discretecomponents, application specific integrated circuits, processorsexecuting appropriate software and the like or any combination thereof.

1. A method for execution by a dispersed storage processing module, themethod comprises: receiving a first request to store a program;determining first error coding dispersal storage function parameters;encoding a data segment of the program in accordance with the firsterror coding dispersal storage function parameters; determining whethera second request to store the program is received; when the secondrequest is not received, encoding a second data segment of the programin accordance with the first error coding dispersal storage functionparameters; when the second request is received, changing the firsterror coding dispersal storage function parameters based on the secondrequest to produce second error coding dispersal storage functionparameters; and encoding the second data segment in accordance with thesecond error coding dispersal storage function parameters.
 2. The methodof claim 1 further comprises: determining whether another request tostore the program is received, wherein the another request is received,in time, between the first and second requests; when the other requestis received, determining whether to change the first error codingdispersal storage function parameters; when the first error codingdispersal storage function parameters are to be changed, changing thefirst error coding dispersal storage function parameters based on theother request to produce third error coding dispersal storage functionparameters; and encoding another data segment in accordance with thethird error coding dispersal storage function parameters.
 3. The methodof claim 1, wherein the changing the first error coding dispersalstorage function parameters based on the second request comprises:changing a post-slice data manipulation function that includes at leastone of: an error injection function; a bit dithering function; a bitrotation function; a slice comparison function; a watermark function; ahash function; and a bit swapping function.
 4. The method of claim 1further comprises at least one of: determining a first playback errorcoding dispersal storage function parameter set for a requesting deviceassociated with the first request based on the first error codingdispersal storage function parameters and subsequent changes to thefirst error coding dispersal storage function parameters; determining asecond playback error coding dispersal storage function parameter setfor a second requesting device associated with the second request basedon the second error coding dispersal storage function parameters andsubsequent changes to the second error coding dispersal storage functionparameters; outputting the first playback error coding dispersal storagefunction parameter set to the first requesting device; and outputtingthe second playback error coding dispersal storage function parameterset to the second requesting device.
 5. The method of claim 1, whereinthe first and second error coding dispersal storage function parameterscomprises one or more of: a pillars list; a segmenting protocol; apre-slice data manipulation function; a forward error correctionencoding function; a slicing pillar width; a post-slice datamanipulation function; a write threshold; and a read threshold.
 6. Themethod of claim 5, wherein the pillars list comprises one of: at leastone set of pillar identifiers associated with less than a slicing pillarwidth number and at least the read threshold number of a plurality of DSunits; and at least one set of pillar identifiers associated with lessthan the slicing pillar width number and at least the read thresholdnumber of the plurality of DS units, wherein the at least one set ofpillar identifiers is unique as compared to every other set of pillaridentifiers associated with previously determined playback error codingdispersal storage function parameter set for the program.
 7. A methodfor execution by a dispersed storage processing module, the methodcomprises: receiving a plurality of requests to retrieve a storedprogram that is stored as a plurality of sets of encoded data slices;for each of the plurality of requests, determining playback error codingdispersal storage function parameters based on the request to produce aplurality of determined playback error coding dispersal storage functionparameters; for a first one of the plurality of requests: retrieving afirst set of the plurality of sets of encoded data slices based on afirst one of the plurality of determined playback error coding dispersalstorage function parameters; and outputting the first set of theplurality of sets of encoded data slices to a first requesting deviceassociated with the first one of the plurality of requests; for a secondone of the plurality of requests: retrieving a second set of theplurality of sets of encoded data slices based on a second one of theplurality of determined playback error coding dispersal storage functionparameters; and outputting the second set of the plurality of sets ofencoded data slices to a second requesting device associated with thesecond one of the plurality of requests.
 8. The method of claim 7,wherein the outputting comprises at least one of: decoding the first setof the plurality of sets of encoded data slices based on the first oneof the plurality of determined playback error coding dispersal storagefunction parameters to produce first recovered data; outputting thefirst recovered data to the first requesting device associated with thefirst one of the plurality of requests; decoding the second set of theplurality of sets of encoded data slices based on the second one of theplurality of determined playback error coding dispersal storage functionparameters to produce second recovered data; and outputting the secondrecovered data to the second requesting device associated with thesecond one of the plurality of requests.
 9. The method of claim 8,wherein the playback error coding dispersal storage function parameterscomprises one or more of: a pillars list; a segmenting protocol; apre-slice data manipulation function; a forward error correctionencoding function; a slicing pillar width; a write threshold; a readthreshold; and a post-slice data manipulation function that includes atleast one of: an error injection function; a bit dithering function; abit rotation function; a slice comparison function; a hash function; anda bit swapping function.
 10. The method of claim 9, wherein the pillarslist comprises one of: at least one set of pillar identifiers associatedwith less than a slicing pillar width number and at least the readthreshold number of a plurality of DS units; and at least one set ofpillar identifiers associated with less than the slicing pillar widthnumber and at least the read threshold number of the plurality of DSunits, wherein the at least one set of pillar identifiers is unique ascompared to every other set of pillar identifiers associated withpreviously determined playback error coding dispersal storage functionparameter set for the recovered data.
 11. A computer comprises: aninterface; and a processing module operable to: receive, via theinterface, a first request to store a program; determine first errorcoding dispersal storage function parameters; encode a data segment ofthe program in accordance with the first error coding dispersal storagefunction parameters; determine whether a second request to store theprogram is received; encode a second data segment of the program inaccordance with the first error coding dispersal storage functionparameters when the second request is not received; change the firsterror coding dispersal storage function parameters based on the anotherrequest to produce second error coding dispersal storage functionparameters when the second request is received; and encode the seconddata segment in accordance with the second error coding dispersalstorage function parameters.
 12. The computer of claim 11, wherein theprocessing module further functions to: determine whether anotherrequest to store the program is received, wherein the another request isreceived, via the interface, in time, between the first and secondrequests; determine whether to change the first error coding dispersalstorage function parameters when the other request is received; changethe first error coding dispersal storage function parameters based onthe other request to produce third error coding dispersal storagefunction parameters when the first error coding dispersal storagefunction parameters are to be changed; and encoding another data segmentin accordance with the third error coding dispersal storage functionparameters.
 13. The computer of claim 11, wherein the processing modulefurther functions to change the first error coding dispersal storagefunction parameters based on the other request by: changing a post-slicedata manipulation function that includes at least one of: an errorinjection function; a bit dithering function; a bit rotation function; aslice comparison function; a watermark function; a hash function; and abit swapping function.
 14. The computer of claim 11, wherein theprocessing module further functions to perform at least one of:determining a first playback error coding dispersal storage functionparameter set for a requesting device associated with the first requestbased on the first error coding dispersal storage function parametersand subsequent changes to the first error coding dispersal storagefunction parameters; determining a second playback error codingdispersal storage function parameter set for a second requesting deviceassociated with the second request based on the second error codingdispersal storage function parameters and subsequent changes to thesecond error coding dispersal storage function parameters; outputting,via the interface, the first playback error coding dispersal storagefunction parameter set to the first requesting device; and outputting,via the interface, the second playback error coding dispersal storagefunction parameter set to the second requesting device.
 15. The computerof claim 11, wherein the first and second error coding dispersal storagefunction parameters comprises one or more of: a pillars list; asegmenting protocol; a pre-slice data manipulation function; a forwarderror correction encoding function; a slicing pillar width; a post-slicedata manipulation function; a write threshold; and a read threshold. 16.The computer of claim 15, wherein the pillars list comprises one of: atleast one set of pillar identifiers associated with less than a slicingpillar width number and at least the read threshold number of aplurality of DS units; and at least one set of pillar identifiersassociated with less than the slicing pillar width number and at leastthe read threshold number of the plurality of DS units, wherein the atleast one set of pillar identifiers is unique as compared to every otherset of pillar identifiers associated with previously determined playbackerror coding dispersal storage function parameter set for the program.17. A computer comprises: an interface; and a processing module operableto: receive, via the interface, a plurality of requests to retrieve astored program that is stored as a plurality of sets of encoded dataslices; determine playback error coding dispersal storage functionparameters based on the request to produce a plurality of determinedplayback error coding dispersal storage function parameters for each ofthe plurality of requests; for a first one of the plurality of requests:retrieve, via the interface, a first set of the plurality of sets ofencoded data slices based on a first one of the plurality of determinedplayback error coding dispersal storage function parameters; and output,via the interface, the first set of the plurality of sets of encodeddata slices to a first requesting device associated with the first oneof the plurality of requests; for a second one of the plurality ofrequests: retrieve, via the interface, a second set of the plurality ofsets of encoded data slices based on a second one of the plurality ofdetermined playback error coding dispersal storage function parameters;and output, via the interface, the second set of the plurality of setsof encoded data slices to a second requesting device associated with thesecond one of the plurality of requests.
 18. The computer of claim 17,wherein the processing module functions to output by at least one of:decoding the first set of the plurality of sets of encoded data slicesbased on the first one of the plurality of determined playback errorcoding dispersal storage function parameters to produce first recovereddata; outputting, via the interface, the first recovered data to thefirst requesting device associated with the first one of the pluralityof requests; decoding the second set of the plurality of sets of encodeddata slices based on the second one of the plurality of determinedplayback error coding dispersal storage function parameters to producesecond recovered data; and outputting, via the interface, the secondrecovered data to the second requesting device associated with thesecond one of the plurality of requests.
 19. The computer of claim 18,wherein the playback error coding dispersal storage function parameterscomprises one or more of: a pillars list; a segmenting protocol; apre-slice data manipulation function; a forward error correctionencoding function; a slicing pillar width; a write threshold; a readthreshold; and a post-slice data manipulation function that includes atleast one of: an error injection function; a bit dithering function; abit rotation function; a slice comparison function; a hash function; anda bit swapping function.
 20. The computer of claim 19, wherein thepillars list comprises one of: at least one set of pillar identifiersassociated with less than a slicing pillar width number and at least theread threshold number of a plurality of DS units; and at least one setof pillar identifiers associated with less than the slicing pillar widthnumber and at least the read threshold number of the plurality of DSunits, wherein the at least one set of pillar identifiers is unique ascompared to every other set of pillar identifiers associated withpreviously determined playback error coding dispersal storage functionparameter set for the recovered data.